private void TraverseInstructions(GraphBuilderContext context, long entrypoint, IEnumerable <long> knownBlockHeaders)
{
var agenda = new Stack <SymbolicProgramState <TInstruction> >();
foreach (var header in knownBlockHeaders)
{
agenda.Push(TransitionResolver.GetInitialState(header));
}
agenda.Push(TransitionResolver.GetInitialState(entrypoint));
while (agenda.Count > 0)
{
// Merge the current state with the recorded states.
var currentState = agenda.Pop();
bool recordedStatesChanged = ApplyStateChange(context, ref currentState);
// If anything changed, we must invalidate the known successors of the current
// instruction and (re)visit all its successors.
if (recordedStatesChanged)
{
var instruction = Instructions.GetCurrentInstruction(currentState);
if (context.Result.ContainsInstruction(currentState.ProgramCounter))
{
context.Result.ClearSuccessors(instruction);
}
else
{
context.Result.AddInstruction(instruction);
}
ResolveAndScheduleSuccessors(context, currentState, instruction, agenda);
}
}
}
/// <inheritdoc />
protected override IInstructionTraversalResult <TInstruction> CollectInstructions(
long entrypoint, IEnumerable <long> knownBlockHeaders)
{
using var context = new GraphBuilderContext(Architecture);
long[] blockHeaders = knownBlockHeaders as long[] ?? knownBlockHeaders.ToArray();
// Perform traversal.
TraverseInstructions(context, entrypoint, blockHeaders);
// Register known block headers.
context.Result.BlockHeaders.Add(entrypoint);
context.Result.BlockHeaders.UnionWith(blockHeaders);
// Infer remaining block headers.
DetermineBlockHeaders(context);
return(context.Result);
}
private static bool ApplyStateChange(
GraphBuilderContext context,
ref SymbolicProgramState <TInstruction> currentState)
{
bool changed;
if (context.RecordedStates.TryGetValue(currentState.ProgramCounter, out var recordedState))
{
// We are revisiting this address, merge program states.
changed = recordedState.MergeStates(currentState, out currentState);
if (changed)
{
context.RecordedStates[currentState.ProgramCounter] = currentState;
}
}
else
{
// This is a new unvisited address.
context.RecordedStates.Add(currentState.ProgramCounter, currentState);
changed = true;
}
return(changed);
}
private void ResolveAndScheduleSuccessors(
GraphBuilderContext context,
SymbolicProgramState <TInstruction> currentState,
in TInstruction instruction,
