/// <summary>
/// Creates and adds a new node to the collection of data flow nodes.
/// </summary>
/// <param name="id">The unique identifier of the node.</param>
/// <param name="contents">The contents of the node.</param>
/// <returns>The created node.</returns>
public DataFlowNode <TContents> Add(long id, TContents contents)
{
var node = new DataFlowNode <TContents>(id, contents);
Add(node);
return(node);
}
private void CollectStackDependencies(
BasicBlock <Statement <TInstruction> > block,
DataFlowNode <TInstruction> dataFlowNode,
Span <IVariable> buffer,
ref int phiStatementCount)
{
var stackDependencies = dataFlowNode.StackDependencies;
for (int i = 0; i < stackDependencies.Count; i++)
{
var sources = stackDependencies[i];
if (sources.Count == 1)
{
// If the dependency only has 1 possible data source, we can simply
// create a stack slot and an assignment to that slot.
buffer[i] = GetStackSlot(sources.First());
}
else
{
// If we have more than 1 possible data source, we
// will add a "phi" node. This basically means
// that the result of the "phi function" will return
// the value based on prior control flow.
var phi = CreatePhiSlot();
var slots = sources
.Select(source => new VariableExpression <TInstruction>(GetStackSlot(source)))
.ToArray();
block.Instructions.Insert(phiStatementCount++, new PhiStatement <TInstruction>(phi, slots));
buffer[i] = phi;
}
}
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="symbol">ISymbol</param>
/// <param name="dfgNode">DataFlowNode</param>
internal SymbolDefinition(ISymbol symbol, DataFlowNode dfgNode)
{
this.DataFlowNode = dfgNode;
this.Symbol = symbol;
this.CandidateTypes = new HashSet<ITypeSymbol>();
this.Kind = symbol.Kind;
this.Name = $"[{this.DataFlowNode.Id},{this.Kind}]::{this.Symbol.Name}";
}
public void AddNodeToGraphShouldSetParentGraph()
{
var dfg = new DataFlowGraph <int>(IntArchitecture.Instance);
var node = new DataFlowNode <int>(1, 2);
dfg.Nodes.Add(node);
Assert.Same(dfg, node.ParentGraph);
}
/// <inheritdoc />
public bool Contains(DataFlowNode <TContents> item)
{
if (item == null)
{
return(false);
}
return(_nodes.TryGetValue(item.Id, out var node) && node == item);
}
public void RemoveNodeFromGraphShouldUnsetParentGraph()
{
var dfg = new DataFlowGraph <int>(IntArchitecture.Instance);
var node = new DataFlowNode <int>(1, 2);
dfg.Nodes.Add(node);
dfg.Nodes.Remove(node);
Assert.Null(node.ParentGraph);
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="dfgNode">DataFlowNode</param>
/// <param name="context">AnalysisContext</param>
internal DataFlowInfo(DataFlowNode dfgNode, AnalysisContext context)
{
this.AnalysisContext = context;
this.DataFlowNode = dfgNode;
this.GeneratedDefinitions = new HashSet<SymbolDefinition>();
this.KilledDefinitions = new HashSet<SymbolDefinition>();
this.InputDefinitions = new HashSet<SymbolDefinition>();
this.OutputDefinitions = new HashSet<SymbolDefinition>();
this.TaintedDefinitions = new Dictionary<SymbolDefinition, ISet<SymbolDefinition>>();
}
public void DisconnectNodeShouldRemoveEdge(DataDependencyType edgeType, bool removeSourceNode)
{
var variable = new DummyVariable("var");
var graph = new DataFlowGraph <int>(IntArchitecture.Instance);
var n1 = new DataFlowNode <int>(0, 0);
n1.StackDependencies.Add(new DataDependency <int>());
n1.VariableDependencies.Add(variable, new DataDependency <int>());
var n2 = new DataFlowNode <int>(1, 1);
graph.Nodes.AddRange(new[]
{
n1,
n2
});
switch (edgeType)
{
case DataDependencyType.Stack:
n1.StackDependencies[0].Add(new DataSource <int>(n2));
break;
case DataDependencyType.Variable:
n1.VariableDependencies[variable].Add(new DataSource <int>(n2));
break;
default:
throw new ArgumentOutOfRangeException(nameof(edgeType), edgeType, null);
}
if (removeSourceNode)
{
n1.Disconnect();
}
else
{
n2.Disconnect();
}
Assert.Empty(n1.StackDependencies[0]);
Assert.Empty(n1.VariableDependencies[variable]);
Assert.Empty(n2.GetDependants());
}
/// <inheritdoc />
public void Add(DataFlowNode <TContents> item)
{
if (item.ParentGraph == _owner)
{
return;
}
if (item.ParentGraph != null)
{
throw new ArgumentException("Cannot add a node from another graph.");
}
if (_nodes.ContainsKey(item.Id))
{
throw new ArgumentException($"A node with identifier 0x{item.Id:X8} was already added to the graph.");
}
_nodes.Add(item.Id, item);
item.ParentGraph = _owner;
}
/// <summary>
/// Collects all dependency nodes recursively, and sorts them in a topological order such that the final collection
/// of nodes can be executed sequentially.
/// </summary>
/// <param name="node">The node to find all dependencies for.</param>
/// <param name="flags">Flags that influence the behaviour of the algorithm.</param>
/// <typeparam name="T">The type of contents that each node contains.</typeparam>
/// <returns>The topological ordering of all dependencies of the node.</returns>
/// <exception cref="CyclicDependencyException">Occurs when there is a cyclic dependency in the graph.</exception>
public static IEnumerable <DataFlowNode <T> > GetOrderedDependencies <T>(this DataFlowNode <T> node, DependencyCollectionFlags flags)
{
try
{
var topologicalSorting = new TopologicalSorter <DataFlowNode <T> >(GetSortedOutgoingEdges);
return(topologicalSorting.GetTopologicalSorting(node));
}
catch (CycleDetectedException ex)
{
throw new CyclicDependencyException("Cyclic dependency was detected.", ex);
}
IReadOnlyList <DataFlowNode <T> > GetSortedOutgoingEdges(DataFlowNode <T> n)
{
var result = new List <DataFlowNode <T> >();
// Prioritize stack dependencies over variable dependencies.
if ((flags & DependencyCollectionFlags.IncludeStackDependencies) != 0)
{
foreach (var dependency in n.StackDependencies)
{
if (dependency.HasKnownDataSources)
{
result.Add(dependency.First().Node);
}
}
}
if ((flags & DependencyCollectionFlags.IncludeVariableDependencies) != 0)
{
foreach (var entry in n.VariableDependencies)
{
if (entry.Value.HasKnownDataSources)
{
result.Add(entry.Value.First().Node);
}
}
}
return(result);
}
}
/// <summary>
/// Creates a new stack data source, referencing a stack value produced by the provided node.
/// </summary>
/// <param name="node">The node producing the value.</param>
/// <param name="slotIndex">The index of the stack value that was produced by the node.</param>
public StackDataSource(DataFlowNode <TContents> node, int slotIndex)
: base(node)
{
SlotIndex = slotIndex;
}
/// <summary>
/// Creates a new stack data source, referencing the first stack value produced by the provided node.
/// </summary>
/// <param name="node">The node producing the value.</param>
public StackDataSource(DataFlowNode <TContents> node)
: base(node)
{
}
/// <summary> /// Collects all dependency nodes recursively, and sorts them in a topological order such that the final collection /// of nodes can be executed sequentially. /// </summary> /// <param name="node">The node to find all dependencies for.</param> /// <typeparam name="T">The type of contents that each node contains.</typeparam> /// <returns>The topological ordering of all dependencies of the node.</returns> /// <exception cref="CyclicDependencyException">Occurs when there is a cyclic dependency in the graph.</exception> public static IEnumerable <DataFlowNode <T> > GetOrderedDependencies <T>(this DataFlowNode <T> node) => GetOrderedDependencies(node, DependencyCollectionFlags.IncludeAllDependencies);
internal VariableDependencyCollection(DataFlowNode <TContents> owner)
{
_owner = owner ?? throw new ArgumentNullException(nameof(owner));
}
/// <inheritdoc /> public bool Remove(DataFlowNode <TContents> item) => item != null && Remove(item.Id);
private void CollectVariableDependencies(
BasicBlock <Statement <TInstruction> > block,
DataFlowNode <TInstruction> dataFlowNode,
Span <IVariable> buffer,
ref int phiStatementCount)
{
int index = 0;
var variableDependencies = dataFlowNode.VariableDependencies;
foreach (var pair in variableDependencies)
{
var variable = pair.Key;
var dependency = pair.Value;
if (dependency.Count <= 1)
{
// If the dependency has only 1 possible source we just simply
// get the variable. But since the AST utilizes SSA, all of the
// variables are versioned. This is good because everything is
// "immutable". One "real" variable will have a new versioned
// variable created every time it is assigned to.
int version = _context.GetVariableVersion(variable);
var snapshot = new VariableSnapshot(variable, version);
buffer[index++] = _context.GetVersionedVariable(snapshot);
continue;
}
// Otherwise (>0), we will get the list of versioned(!) variables
// that could reach the instruction and create a "phi" statement
// like in the stack dependencies.
var sources = CollectVariables();
if (_context.VariableSourcesToPhiVariable.TryGetValue(sources, out var phi))
{
// If a phi slot already exists for the list of variables,
// reuse the same phi slot.
buffer[index++] = phi;
}
else
{
// Otherwise, create a new phi slot for the list of variables
// and save it if we encounter the same variables again.
phi = CreatePhiSlot();
var slots = sources
.Select(source => new VariableExpression <TInstruction>(source))
.ToArray();
_context.VariableSourcesToPhiVariable.Add(sources, phi);
block.Instructions.Insert(phiStatementCount++, new PhiStatement <TInstruction>(phi, slots));
buffer[index++] = phi;
}
List <AstVariable> CollectVariables()
{
var result = new List <AstVariable>();
foreach (var instruction in dependency.Select(dep => dep.Node.Contents))
{
if (_context.VariableStates.TryGetValue(instruction, out var versions))
{
// If we already have a dictionary for the instruction, we will
// just get the versioned variable from the existing dictionary.
var snapshot = new VariableSnapshot(variable, versions[variable]);
result.Add(_context.VersionedVariables[snapshot]);
}
else
{
// Otherwise, we will create a new dictionary for the instruction.
var snapshot = new VariableSnapshot(variable, 0);
var slot = _context.GetVersionedVariable(snapshot);
_context.VariableStates.Add(instruction, new Dictionary <IVariable, int>
{
[variable] = 0
});
result.Add(slot);
}
}
return(result);
}
}
}
/// <summary>
/// Creates a new symbolic value with a single data source.
/// </summary>
/// <param name="dataSource">The data source of the symbolic value.</param>
public SymbolicValue(DataFlowNode <T> dataSource)
: this(new DataSource <T>(dataSource, 0))
{
}
public void ConstructorShouldSetContents()
{
var node = new DataFlowNode <int>(1, 2);
Assert.Equal(2, node.Contents);
}
