/// <summary>
/// Performs data flow analysis on the given control flow graph node.
/// </summary>
/// <param name="cfgNode">ControlFlowGraphNode</param>
/// <param name="previousCfgNode">Previous controlFlowGraphNode</param>
/// <param name="previousSyntaxNode">Previous syntaxNode</param>
/// <param name="dataFlowMap">DataFlowMap</param>
/// <param name="model">SemanticModel</param>
/// <param name="context">AnalysisContext</param>
/// <returns>Boolean</returns>
private static void AnalyseControlFlowGraphNode(ControlFlowGraphNode cfgNode, ControlFlowGraphNode previousCfgNode,
SyntaxNode previousSyntaxNode, DataFlowMap dataFlowMap, SemanticModel model, AnalysisContext context)
{
if (!cfgNode.IsJumpNode && !cfgNode.IsLoopHeadNode)
{
foreach (var syntaxNode in cfgNode.SyntaxNodes)
{
dataFlowMap.Transfer(previousSyntaxNode, previousCfgNode, syntaxNode, cfgNode);
var stmt = syntaxNode as StatementSyntax;
var localDecl = stmt.DescendantNodesAndSelf().OfType<LocalDeclarationStatementSyntax>().FirstOrDefault();
var expr = stmt.DescendantNodesAndSelf().OfType<ExpressionStatementSyntax>().FirstOrDefault();
var ret = stmt.DescendantNodesAndSelf().OfType<ReturnStatementSyntax>().FirstOrDefault();
if (localDecl != null)
{
var varDecl = (stmt as LocalDeclarationStatementSyntax).Declaration;
foreach (var variable in varDecl.Variables)
{
if (variable.Initializer == null)
{
continue;
}
DataFlowAnalysis.TryCaptureParameterAccess(variable.Initializer.Value,
syntaxNode, cfgNode, dataFlowMap, model, context);
DataFlowAnalysis.TryCaptureFieldAccess(variable.Initializer.Value,
syntaxNode, cfgNode, dataFlowMap, model, context);
ITypeSymbol declType = null;
if (variable.Initializer.Value is LiteralExpressionSyntax &&
variable.Initializer.Value.IsKind(SyntaxKind.NullLiteralExpression))
{
declType = model.GetTypeInfo(varDecl.Type).Type;
}
else
{
declType = model.GetTypeInfo(variable.Initializer.Value).Type;
}
if (context.IsTypeAllowedToBeSend(declType) ||
context.IsMachineType(declType, model))
{
continue;
}
var declSymbol = model.GetDeclaredSymbol(variable);
if (variable.Initializer.Value is IdentifierNameSyntax ||
variable.Initializer.Value is MemberAccessExpressionSyntax)
{
ISymbol varSymbol = null;
if (variable.Initializer.Value is IdentifierNameSyntax)
{
varSymbol = model.GetSymbolInfo(variable.Initializer.Value
as IdentifierNameSyntax).Symbol;
}
else if (variable.Initializer.Value is MemberAccessExpressionSyntax)
{
varSymbol = model.GetSymbolInfo((variable.Initializer.Value
as MemberAccessExpressionSyntax).Name).Symbol;
}
dataFlowMap.MapRefToSymbol(varSymbol, declSymbol, syntaxNode, cfgNode);
HashSet<ITypeSymbol> objectTypes = null;
if (DataFlowAnalysis.ResolveObjectType(out objectTypes, varSymbol, syntaxNode,
cfgNode, dataFlowMap))
{
dataFlowMap.MapObjectTypesToSymbol(objectTypes, declSymbol, syntaxNode, cfgNode);
}
else
{
dataFlowMap.EraseObjectTypesFromSymbol(declSymbol, syntaxNode, cfgNode);
}
}
else if (variable.Initializer.Value is LiteralExpressionSyntax &&
variable.Initializer.Value.IsKind(SyntaxKind.NullLiteralExpression))
{
dataFlowMap.ResetSymbol(declSymbol, syntaxNode, cfgNode);
}
else if (variable.Initializer.Value is InvocationExpressionSyntax)
{
var invocation = variable.Initializer.Value as InvocationExpressionSyntax;
var summary = MethodSummary.TryGetSummary(invocation, model, context);
var reachableSymbols = DataFlowAnalysis.ResolveSideEffectsInCall(invocation,
summary, syntaxNode, cfgNode, model, dataFlowMap);
var returnSymbols = DataFlowAnalysis.GetReturnSymbols(invocation, summary, model);
if (returnSymbols.Count == 0)
{
dataFlowMap.ResetSymbol(declSymbol, syntaxNode, cfgNode);
}
else if (returnSymbols.Contains(declSymbol))
{
dataFlowMap.MapRefsToSymbol(returnSymbols, declSymbol, syntaxNode, cfgNode, false);
}
else
{
dataFlowMap.MapRefsToSymbol(returnSymbols, declSymbol, syntaxNode, cfgNode);
}
if (reachableSymbols.Count > 0)
{
dataFlowMap.MapReachableFieldsToSymbol(reachableSymbols, declSymbol,
syntaxNode, cfgNode);
}
if (summary != null && summary.ReturnTypeSet.Count > 0)
{
dataFlowMap.MapObjectTypesToSymbol(summary.ReturnTypeSet,
declSymbol, syntaxNode, cfgNode);
}
else
{
dataFlowMap.EraseObjectTypesFromSymbol(declSymbol, syntaxNode, cfgNode);
}
}
else if (variable.Initializer.Value is ObjectCreationExpressionSyntax)
{
var objCreation = variable.Initializer.Value as ObjectCreationExpressionSyntax;
var summary = MethodSummary.TryGetSummary(objCreation, model, context);
var reachableSymbols = DataFlowAnalysis.ResolveSideEffectsInCall(objCreation,
summary, syntaxNode, cfgNode, model, dataFlowMap);
var returnSymbols = DataFlowAnalysis.GetReturnSymbols(objCreation, summary, model);
if (returnSymbols.Count == 0)
{
dataFlowMap.ResetSymbol(declSymbol, syntaxNode, cfgNode);
}
else if (returnSymbols.Contains(declSymbol))
{
dataFlowMap.MapRefsToSymbol(returnSymbols, declSymbol, syntaxNode, cfgNode, false);
}
else
{
dataFlowMap.MapRefsToSymbol(returnSymbols, declSymbol, syntaxNode, cfgNode);
}
if (reachableSymbols.Count > 0)
{
dataFlowMap.MapReachableFieldsToSymbol(reachableSymbols, declSymbol,
syntaxNode, cfgNode);
}
var typeSymbol = model.GetSymbolInfo(objCreation.Type).Symbol as ITypeSymbol;
if (typeSymbol != null)
{
dataFlowMap.MapObjectTypesToSymbol(new HashSet<ITypeSymbol> { typeSymbol },
declSymbol, syntaxNode, cfgNode);
}
else
{
dataFlowMap.EraseObjectTypesFromSymbol(declSymbol, syntaxNode, cfgNode);
}
}
}
}
else if (expr != null)
{
if (expr.Expression is BinaryExpressionSyntax)
{
var binaryExpr = expr.Expression as BinaryExpressionSyntax;
DataFlowAnalysis.TryCaptureParameterAccess(binaryExpr.Left,
syntaxNode, cfgNode, dataFlowMap, model, context);
DataFlowAnalysis.TryCaptureParameterAccess(binaryExpr.Right,
syntaxNode, cfgNode, dataFlowMap, model, context);
DataFlowAnalysis.TryCaptureFieldAccess(binaryExpr.Left,
syntaxNode, cfgNode, dataFlowMap, model, context);
DataFlowAnalysis.TryCaptureFieldAccess(binaryExpr.Right,
syntaxNode, cfgNode, dataFlowMap, model, context);
IdentifierNameSyntax lhs = null;
ISymbol lhsFieldSymbol = null;
if (binaryExpr.Left is IdentifierNameSyntax)
{
lhs = binaryExpr.Left as IdentifierNameSyntax;
var lhsType = model.GetTypeInfo(lhs).Type;
if (context.IsTypeAllowedToBeSend(lhsType) ||
context.IsMachineType(lhsType, model))
{
previousSyntaxNode = syntaxNode;
previousCfgNode = cfgNode;
continue;
}
}
else if (binaryExpr.Left is MemberAccessExpressionSyntax)
{
var name = (binaryExpr.Left as MemberAccessExpressionSyntax).Name;
var lhsType = model.GetTypeInfo(name).Type;
if (context.IsTypeAllowedToBeSend(lhsType) ||
context.IsMachineType(lhsType, model))
{
previousSyntaxNode = syntaxNode;
previousCfgNode = cfgNode;
continue;
}
lhs = context.GetFirstNonMachineIdentifier(binaryExpr.Left, model);
lhsFieldSymbol = model.GetSymbolInfo(name as IdentifierNameSyntax).Symbol;
}
else if (binaryExpr.Left is ElementAccessExpressionSyntax)
{
var memberAccess = (binaryExpr.Left as ElementAccessExpressionSyntax);
if (memberAccess.Expression is IdentifierNameSyntax)
{
lhs = memberAccess.Expression as IdentifierNameSyntax;
var lhsType = model.GetTypeInfo(lhs).Type;
if (context.IsTypeAllowedToBeSend(lhsType) ||
context.IsMachineType(lhsType, model))
{
previousSyntaxNode = syntaxNode;
previousCfgNode = cfgNode;
continue;
}
}
else if (memberAccess.Expression is MemberAccessExpressionSyntax)
{
var name = (memberAccess.Expression as MemberAccessExpressionSyntax).Name;
var lhsType = model.GetTypeInfo(name).Type;
if (context.IsTypeAllowedToBeSend(lhsType) ||
context.IsMachineType(lhsType, model))
{
previousSyntaxNode = syntaxNode;
previousCfgNode = cfgNode;
continue;
}
lhs = context.GetFirstNonMachineIdentifier(memberAccess.Expression, model);
lhsFieldSymbol = model.GetSymbolInfo(name as IdentifierNameSyntax).Symbol;
}
}
var leftSymbol = model.GetSymbolInfo(lhs).Symbol;
if (binaryExpr.Right is IdentifierNameSyntax ||
binaryExpr.Right is MemberAccessExpressionSyntax)
{
IdentifierNameSyntax rhs = null;
if (binaryExpr.Right is IdentifierNameSyntax)
{
rhs = binaryExpr.Right as IdentifierNameSyntax;
}
else if (binaryExpr.Right is MemberAccessExpressionSyntax)
{
rhs = context.GetFirstNonMachineIdentifier(binaryExpr.Right, model);
}
var rightSymbol = model.GetSymbolInfo(rhs).Symbol;
dataFlowMap.MapRefToSymbol(rightSymbol, leftSymbol, syntaxNode, cfgNode);
if (lhsFieldSymbol != null && !lhsFieldSymbol.Equals(leftSymbol))
{
dataFlowMap.MapRefToSymbol(rightSymbol, lhsFieldSymbol, syntaxNode, cfgNode);
}
HashSet<ITypeSymbol> objectTypes = null;
if (DataFlowAnalysis.ResolveObjectType(out objectTypes, rightSymbol, syntaxNode,
cfgNode, dataFlowMap))
{
dataFlowMap.MapObjectTypesToSymbol(objectTypes, leftSymbol, syntaxNode, cfgNode);
}
else
{
dataFlowMap.EraseObjectTypesFromSymbol(leftSymbol, syntaxNode, cfgNode);
}
}
else if (binaryExpr.Right is LiteralExpressionSyntax &&
binaryExpr.Right.IsKind(SyntaxKind.NullLiteralExpression))
{
dataFlowMap.ResetSymbol(leftSymbol, syntaxNode, cfgNode);
if (lhsFieldSymbol != null && !lhsFieldSymbol.Equals(leftSymbol))
{
dataFlowMap.ResetSymbol(lhsFieldSymbol, syntaxNode, cfgNode);
}
}
else if (binaryExpr.Right is InvocationExpressionSyntax)
{
var invocation = binaryExpr.Right as InvocationExpressionSyntax;
var summary = MethodSummary.TryGetSummary(invocation, model, context);
var reachableSymbols = DataFlowAnalysis.ResolveSideEffectsInCall(invocation,
summary, syntaxNode, cfgNode, model, dataFlowMap);
var returnSymbols = DataFlowAnalysis.GetReturnSymbols(invocation,
summary, model);
DataFlowAnalysis.CheckForNonMappedFieldSymbol(invocation, cfgNode,
dataFlowMap, model, context);
if (returnSymbols.Count == 0)
{
dataFlowMap.ResetSymbol(leftSymbol, syntaxNode, cfgNode);
if (lhsFieldSymbol != null && !lhsFieldSymbol.Equals(leftSymbol))
{
dataFlowMap.ResetSymbol(lhsFieldSymbol, syntaxNode, cfgNode);
}
}
else if (returnSymbols.Contains(leftSymbol))
{
dataFlowMap.MapRefsToSymbol(returnSymbols, leftSymbol, syntaxNode, cfgNode, false);
if (lhsFieldSymbol != null && !lhsFieldSymbol.Equals(leftSymbol))
{
dataFlowMap.MapRefsToSymbol(returnSymbols, lhsFieldSymbol,
syntaxNode, cfgNode, false);
}
}
else
{
dataFlowMap.MapRefsToSymbol(returnSymbols, leftSymbol, syntaxNode, cfgNode);
if (lhsFieldSymbol != null && !lhsFieldSymbol.Equals(leftSymbol))
{
dataFlowMap.MapRefsToSymbol(returnSymbols, lhsFieldSymbol,
syntaxNode, cfgNode);
}
}
if (lhsFieldSymbol != null && reachableSymbols.Count > 0)
{
dataFlowMap.MapReachableFieldsToSymbol(reachableSymbols, lhsFieldSymbol,
syntaxNode, cfgNode);
}
if (summary != null && summary.ReturnTypeSet.Count > 0)
{
dataFlowMap.MapObjectTypesToSymbol(summary.ReturnTypeSet,
leftSymbol, syntaxNode, cfgNode);
}
else
{
dataFlowMap.EraseObjectTypesFromSymbol(leftSymbol, syntaxNode, cfgNode);
}
}
else if (binaryExpr.Right is ObjectCreationExpressionSyntax)
{
var objCreation = binaryExpr.Right as ObjectCreationExpressionSyntax;
var summary = MethodSummary.TryGetSummary(objCreation, model, context);
var reachableSymbols = DataFlowAnalysis.ResolveSideEffectsInCall(objCreation,
summary, syntaxNode, cfgNode, model, dataFlowMap);
var returnSymbols = DataFlowAnalysis.GetReturnSymbols(objCreation, summary, model);
if (returnSymbols.Count == 0)
{
dataFlowMap.ResetSymbol(leftSymbol, syntaxNode, cfgNode);
if (lhsFieldSymbol != null && !lhsFieldSymbol.Equals(leftSymbol))
{
dataFlowMap.ResetSymbol(lhsFieldSymbol, syntaxNode, cfgNode);
}
}
else if (returnSymbols.Contains(leftSymbol))
{
dataFlowMap.MapRefsToSymbol(returnSymbols, leftSymbol, syntaxNode, cfgNode, false);
if (lhsFieldSymbol != null && !lhsFieldSymbol.Equals(leftSymbol))
{
dataFlowMap.MapRefsToSymbol(returnSymbols, lhsFieldSymbol,
syntaxNode, cfgNode, false);
}
}
else
{
dataFlowMap.MapRefsToSymbol(returnSymbols, leftSymbol, syntaxNode, cfgNode);
if (lhsFieldSymbol != null && !lhsFieldSymbol.Equals(leftSymbol))
{
dataFlowMap.MapRefsToSymbol(returnSymbols, lhsFieldSymbol,
syntaxNode, cfgNode);
}
}
if (lhsFieldSymbol != null && reachableSymbols.Count > 0)
{
dataFlowMap.MapReachableFieldsToSymbol(reachableSymbols, lhsFieldSymbol,
syntaxNode, cfgNode);
}
var typeSymbol = model.GetSymbolInfo(objCreation.Type).Symbol as ITypeSymbol;
if (typeSymbol != null)
{
dataFlowMap.MapObjectTypesToSymbol(new HashSet<ITypeSymbol> { typeSymbol },
leftSymbol, syntaxNode, cfgNode);
}
else
{
dataFlowMap.EraseObjectTypesFromSymbol(leftSymbol, syntaxNode, cfgNode);
}
}
}
else if (expr.Expression is InvocationExpressionSyntax)
{
var invocation = expr.Expression as InvocationExpressionSyntax;
var summary = MethodSummary.TryGetSummary(invocation, model, context);
DataFlowAnalysis.ResolveSideEffectsInCall(invocation, summary,
syntaxNode, cfgNode, model, dataFlowMap);
DataFlowAnalysis.GetReturnSymbols(invocation, summary, model);
DataFlowAnalysis.CheckForNonMappedFieldSymbol(invocation, cfgNode,
dataFlowMap, model, context);
}
}
else if (ret != null)
{
HashSet<ISymbol> returnSymbols = null;
if (ret.Expression is IdentifierNameSyntax ||
ret.Expression is MemberAccessExpressionSyntax)
{
IdentifierNameSyntax rhs = null;
if (ret.Expression is IdentifierNameSyntax)
{
rhs = ret.Expression as IdentifierNameSyntax;
}
else if (ret.Expression is MemberAccessExpressionSyntax)
{
rhs = context.GetFirstNonMachineIdentifier(ret.Expression, model);
}
var rightSymbol = model.GetSymbolInfo(rhs).Symbol;
returnSymbols = new HashSet<ISymbol> { rightSymbol };
HashSet<ITypeSymbol> objectTypes = null;
if (DataFlowAnalysis.ResolveObjectType(out objectTypes, rightSymbol,
syntaxNode, cfgNode, dataFlowMap))
{
foreach (var objectType in objectTypes)
{
cfgNode.Summary.ReturnTypeSet.Add(objectType);
}
}
}
else if (ret.Expression is InvocationExpressionSyntax)
{
var invocation = ret.Expression as InvocationExpressionSyntax;
var summary = MethodSummary.TryGetSummary(invocation, model, context);
DataFlowAnalysis.ResolveSideEffectsInCall(invocation, summary,
syntaxNode, cfgNode, model, dataFlowMap);
returnSymbols = DataFlowAnalysis.GetReturnSymbols(invocation, summary, model);
if (summary != null)
{
foreach (var objectType in summary.ReturnTypeSet)
{
cfgNode.Summary.ReturnTypeSet.Add(objectType);
}
}
}
else if (ret.Expression is ObjectCreationExpressionSyntax)
{
var objCreation = ret.Expression as ObjectCreationExpressionSyntax;
var summary = MethodSummary.TryGetSummary(objCreation, model, context);
DataFlowAnalysis.ResolveSideEffectsInCall(objCreation, summary,
syntaxNode, cfgNode, model, dataFlowMap);
returnSymbols = DataFlowAnalysis.GetReturnSymbols(objCreation, summary, model);
var objectType = model.GetSymbolInfo(objCreation.Type).Symbol as ITypeSymbol;
if (objectType != null)
{
cfgNode.Summary.ReturnTypeSet.Add(objectType);
}
}
DataFlowAnalysis.TryCaptureReturnSymbols(returnSymbols, syntaxNode,
cfgNode, model, dataFlowMap);
}
previousSyntaxNode = syntaxNode;
previousCfgNode = cfgNode;
}
}
else
{
dataFlowMap.Transfer(previousSyntaxNode, previousCfgNode, cfgNode.SyntaxNodes[0], cfgNode);
previousSyntaxNode = cfgNode.SyntaxNodes[0];
previousCfgNode = cfgNode;
}
foreach (var successor in cfgNode.ISuccessors)
{
if (DataFlowAnalysis.ReachedFixpoint(previousSyntaxNode, cfgNode, successor, dataFlowMap))
{
continue;
}
DataFlowAnalysis.AnalyseControlFlowGraphNode(successor, cfgNode,
previousSyntaxNode, dataFlowMap, model, context);
}
}
/// <summary>
/// Resolves the side effects from the given invocation summary.
/// </summary>
/// <param name="call">Call</param>
/// <param name="summary">MethodSummary</param>
/// <param name="syntaxNode">SyntaxNode</param>
/// <param name="cfgNode">ControlFlowGraphNode</param>
/// <param name="model">SemanticModel</param>
/// <param name="dataFlowMap">DataFlowMap</param>
/// <returns>Set of reachable field symbols</returns>
private static HashSet<ISymbol> ResolveSideEffectsInCall(InvocationExpressionSyntax call, MethodSummary summary,
SyntaxNode syntaxNode, ControlFlowGraphNode cfgNode, SemanticModel model, DataFlowMap dataFlowMap)
{
if (summary == null)
{
return new HashSet<ISymbol>();
}
HashSet<ISymbol> reachableFields = new HashSet<ISymbol>();
var sideEffects = summary.GetResolvedSideEffects(call.ArgumentList, model);
foreach (var sideEffect in sideEffects)
{
dataFlowMap.MapRefsToSymbol(sideEffect.Value, sideEffect.Key, syntaxNode, cfgNode);
reachableFields.Add(sideEffect.Key);
}
foreach (var fieldAccess in summary.FieldAccessSet)
{
foreach (var access in fieldAccess.Value)
{
if (cfgNode.Summary.FieldAccessSet.ContainsKey(fieldAccess.Key as IFieldSymbol))
{
cfgNode.Summary.FieldAccessSet[fieldAccess.Key as IFieldSymbol].Add(access);
}
else
{
cfgNode.Summary.FieldAccessSet.Add(fieldAccess.Key as IFieldSymbol, new HashSet<SyntaxNode>());
cfgNode.Summary.FieldAccessSet[fieldAccess.Key as IFieldSymbol].Add(access);
}
}
}
return reachableFields;
}