private IEnumerable <ProgramState> ProcessSwt(ILInstruction instruction, ProgramState next)
{
var result = new List <ProgramState>();
var symbolicTableSlot = next.Stack.Pop();
var symbolicValue = next.Stack.Pop();
instruction.Dependencies.AddOrMerge(0, symbolicTableSlot);
instruction.Dependencies.AddOrMerge(1, symbolicValue);
var annotation = new JumpAnnotation
{
InferredPopCount = instruction.Dependencies.Count,
InferredPushCount = 0
};
ulong tableAddress = symbolicTableSlot.InferStackValue().U8;
var reader = KoiStream.Contents.CreateReader();
reader.Offset = (uint)(tableAddress - 2);
ushort count = reader.ReadUInt16();
for (int i = 0; i < count; i++)
{
int relativeOffset = reader.ReadInt32();
ulong nextIp = (ulong)((long)next.IP + relativeOffset);
Logger.Debug2(Tag, $"Inferred edge IL_{instruction.Offset:X4} -> IL_{nextIp:X4}");
var caseState = next.Copy();
caseState.IP = nextIp;
result.Add(caseState);
annotation.InferredJumpTargets.Add(nextIp);
}
result.Add(next);
instruction.Annotation = annotation;
return(result);
}
private JumpAnnotation InferJumpTargets(ILInstruction instruction)
{
try
{
var metadata = new JumpAnnotation();
var symbolicAddress = instruction.Dependencies[instruction.Dependencies.Count - 1];
foreach (var dataSource in symbolicAddress.DataSources)
{
var emulator = new InstructionEmulator();
emulator.EmulateDependentInstructions(dataSource);
emulator.EmulateInstruction(dataSource);
// After partial emulation, IP is on stack.
uint nextIp = (uint)emulator.Stack.Pop().U8;
Logger.Debug2(Tag, $"Inferred edge IL_{instruction.Offset:X4} -> IL_{nextIp:X4}");
if (nextIp > (ulong)KoiStream.Contents.GetPhysicalSize())
{
Logger.Warning(Tag,
$"Jump instruction at IL_{instruction.Offset:X4} "
+ $"transfers control to an instruction outside of the KoiVM stream (IL_{nextIp:X4}.");
}
metadata.InferredJumpTargets.Add(nextIp);
}
instruction.Annotation = metadata;
return(metadata);
}
catch (NotSupportedException e)
{
Logger.Warning(Tag, $"Could not infer jump target for {instruction.Offset:X4}. {e.Message}");
}
return(null);
}
