protected override IDictionary <IVariable, IExpression> Flow(CFGNode node, IDictionary <IVariable, IExpression> input)
{
IDictionary <IVariable, IExpression> result;
if (input == null)
{
result = new Dictionary <IVariable, IExpression>();
}
else
{
result = new Dictionary <IVariable, IExpression>(input);
}
foreach (var instruction in node.Instructions)
{
var equality = this.Flow(instruction, result);
foreach (var variable in instruction.ModifiedVariables)
{
this.RemoveEqualitiesWithVariable(result, variable);
}
if (equality.HasValue)
{
result.Add(equality.Value);
}
}
return(result);
}
public void ConnectNodes(CFGNode predecessor, CFGNode successor)
{
successor.Predecessors.Add(predecessor);
predecessor.Successors.Add(successor);
this.Nodes.Add(predecessor);
this.Nodes.Add(successor);
}
private static IDictionary <string, CFGNode> CreateNodes(IEnumerable <Instruction> instructions)
{
var leaders = new Dictionary <string, CFGNode>();
var nextIsLeader = true;
var nodeId = 2;
foreach (var instruction in instructions)
{
var isLeader = nextIsLeader;
nextIsLeader = false;
if (instruction is TryInstruction ||
instruction is CatchInstruction ||
instruction is FinallyInstruction)
{
isLeader = true;
}
if (isLeader && !leaders.ContainsKey(instruction.Label))
{
var node = new CFGNode(nodeId++);
leaders.Add(instruction.Label, node);
}
if (instruction is UnconditionalBranchInstruction ||
instruction is ConditionalBranchInstruction)
{
nextIsLeader = true;
var branch = instruction as BranchInstruction;
if (!leaders.ContainsKey(branch.Target))
{
var node = new CFGNode(nodeId++);
leaders.Add(branch.Target, node);
}
}
else if (instruction is SwitchInstruction)
{
nextIsLeader = true;
var branch = instruction as SwitchInstruction;
foreach (var target in branch.Targets)
{
if (!leaders.ContainsKey(target))
{
var node = new CFGNode(nodeId++);
leaders.Add(target, node);
}
}
}
else if (instruction is ReturnInstruction ||
instruction is ThrowInstruction)
{
nextIsLeader = true;
}
}
return(leaders);
}
protected override Subset <DefinitionInstruction> Flow(CFGNode node, Subset <DefinitionInstruction> input)
{
var output = input.Clone();
var kill = KILL[node.Id];
var gen = GEN[node.Id];
output.Except(kill);
output.Union(gen);
return(output);
}
protected override PointsToGraph Flow(CFGNode node, PointsToGraph input)
{
var ptg = input.Clone();
foreach (var instruction in node.Instructions)
{
this.Flow(ptg, instruction);
}
return(ptg);
}
private static ISet <CFGNode> ComputeDominators(CFGNode node)
{
var result = new HashSet <CFGNode>();
do
{
result.Add(node);
node = node.ImmediateDominator;
}while (node != null);
return(result);
}
protected override IDictionary <IVariable, IVariable> Flow(CFGNode node, IDictionary <IVariable, IVariable> output)
{
var input = new Dictionary <IVariable, IVariable>(output);
var kill = KILL[node.Id];
var gen = GEN[node.Id];
foreach (var variable in kill)
{
this.RemoveCopiesWithVariable(input, variable);
}
input.AddRange(gen);
return(input);
}
private static CFGNode FindCommonAncestor(CFGNode a, CFGNode b)
{
while (a.ForwardIndex != b.ForwardIndex)
{
while (a.ForwardIndex > b.ForwardIndex)
{
a = a.ImmediateDominator;
}
while (b.ForwardIndex > a.ForwardIndex)
{
b = b.ImmediateDominator;
}
}
return(a);
}
private static CFGNode[] ComputeBackwardTopologicalSort(ControlFlowGraph cfg)
{
// reverse postorder traversal from exit node
var stack = new Stack <CFGNode>();
var result = new CFGNode[cfg.Nodes.Count];
var status = new TopologicalSortNodeStatus[cfg.Nodes.Count];
var index = cfg.Nodes.Count - 1;
foreach (var node in cfg.Exits)
{
stack.Push(node);
status[node.Id] = TopologicalSortNodeStatus.FirstVisit;
}
do
{
var node = stack.Peek();
var node_status = status[node.Id];
if (node_status == TopologicalSortNodeStatus.FirstVisit)
{
status[node.Id] = TopologicalSortNodeStatus.SecondVisit;
foreach (var pred in node.Predecessors)
{
var pred_status = status[pred.Id];
if (pred_status == TopologicalSortNodeStatus.NeverVisited)
{
stack.Push(pred);
status[pred.Id] = TopologicalSortNodeStatus.FirstVisit;
}
}
}
else if (node_status == TopologicalSortNodeStatus.SecondVisit)
{
stack.Pop();
node.BackwardIndex = index;
result[index] = node;
index--;
}
}while (stack.Count > 0);
return(result);
}
protected override IDictionary <IVariable, IExpression> InitialValue(CFGNode node)
{
return(GEN[node.Id]);
}
public DataFlowAnalysisResult <IDictionary <IVariable, IExpression> > this[CFGNode node]
{
get { return(this.result[node.Id]); }
}
public CFGEdge(CFGNode source, CFGNode target)
{
this.Source = source;
this.Target = target;
}
protected override Subset <DefinitionInstruction> InitialValue(CFGNode node)
{
return(GEN[node.Id]);
}
//public IExpression Condition { get; set; }
public CFGLoop(CFGNode header)
{
this.Header = header;
this.Body = new HashSet <CFGNode>();
this.Body.Add(header);
}
protected override PointsToGraph InitialValue(CFGNode node)
{
return(this.initialGraph);
}
protected abstract T InitialValue(CFGNode node);
protected abstract T Flow(CFGNode node, T input);
private void RenameVariables(CFGNode node, IDictionary <IVariable, Stack <DerivedVariable> > derived_variables, Dictionary <IVariable, uint> indices)
{
foreach (var instruction in node.Instructions)
{
DerivedVariable result_derived = null;
if (instruction is DefinitionInstruction)
{
var definition = instruction as DefinitionInstruction;
//if (definition.HasResult && indices.ContainsKey(definition.Result))
if (definition.HasResult)
{
var result = definition.Result;
var index = indices[result];
result_derived = new DerivedVariable(result, index);
definition.Result = result_derived;
}
}
foreach (var variable in instruction.UsedVariables)
{
// When the instruction is a phi, its arguments (used variables)
// are already derived variables, so there is no entry in
// derived_variables dictionary for them.
if (!derived_variables.ContainsKey(variable))
{
continue;
}
var stack = derived_variables[variable];
var derived = stack.Peek();
instruction.Replace(variable, derived);
}
if (result_derived != null)
{
var result = result_derived.Original;
var index = result_derived.Index;
var result_stack = derived_variables[result];
result_stack.Push(result_derived);
indices[result] = index + 1;
}
}
foreach (var succ in node.Successors)
{
if (!phi_instructions.ContainsKey(succ))
{
continue;
}
var node_phi_instructions = phi_instructions[succ];
foreach (var entry in node_phi_instructions)
{
var variable = entry.Key;
var phi = entry.Value;
var stack = derived_variables[variable];
var derived = stack.Peek();
phi.Arguments.Add(derived);
}
}
foreach (var child in node.ImmediateDominated)
{
this.RenameVariables(child, derived_variables, indices);
}
foreach (var instruction in node.Instructions)
{
if (instruction is DefinitionInstruction)
{
var definition = instruction as DefinitionInstruction;
if (definition.HasResult)
{
var derived = definition.Result as DerivedVariable;
var result = derived.Original;
var stack = derived_variables[result];
stack.Pop();
}
}
}
}
