/// <summary>
/// Computes a key sequence of the given CFG.
/// </summary>
/// <param name="graph">The CFG.</param>
/// <param name="random">The random source, or <c>null</c> if key id is needed.</param>
/// <returns>The generated key sequence of the CFG.</returns>
public static BlockKey[] ComputeKeys(ControlFlowGraph graph, RandomGenerator random) {
var keys = new BlockKey[graph.Count];
foreach (ControlFlowBlock block in graph) {
var key = new BlockKey();
if ((block.Type & ControlFlowBlockType.Entry) != 0)
key.Type = BlockKeyType.Explicit;
else
key.Type = BlockKeyType.Incremental;
keys[block.Id] = key;
}
ProcessBlocks(keys, graph, random);
return keys;
}
private static void ProcessBlocks(BlockKey[] keys, ControlFlowGraph graph, RandomGenerator random)
{
uint id = 0;
for (int i = 0; i < keys.Length; i++)
{
keys[i].EntryState = id++;
keys[i].ExitState = id++;
}
var finallyIds = new Dictionary <ExceptionHandler, uint>();
var ehMap = new Dictionary <ControlFlowBlock, List <ExceptionHandler> >();
bool updated;
do
{
updated = false;
// Update the state ids with the maximum id
foreach (ControlFlowBlock block in graph)
{
BlockKey key = keys[block.Id];
if (block.Sources.Count > 0)
{
uint newEntry = block.Sources.Select(b => keys[b.Id].ExitState).Max();
if (key.EntryState != newEntry)
{
key.EntryState = newEntry;
updated = true;
}
}
if (block.Targets.Count > 0)
{
uint newExit = block.Targets.Select(b => keys[b.Id].EntryState).Max();
if (key.ExitState != newExit)
{
key.ExitState = newExit;
updated = true;
}
}
if (block.Footer.OpCode.Code == Code.Endfilter || block.Footer.OpCode.Code == Code.Endfinally)
{
// Match the exit state within finally/fault/filter
List <ExceptionHandler> ehs;
if (!ehMap.TryGetValue(block, out ehs))
{
ehs = new List <ExceptionHandler>();
int footerIndex = graph.IndexOf(block.Footer);
foreach (var eh in graph.Body.ExceptionHandlers)
{
if (eh.FilterStart != null && block.Footer.OpCode.Code == Code.Endfilter)
{
if (footerIndex >= graph.IndexOf(eh.FilterStart) &&
footerIndex < graph.IndexOf(eh.HandlerStart))
{
ehs.Add(eh);
}
}
else if (eh.HandlerType == ExceptionHandlerType.Finally ||
eh.HandlerType == ExceptionHandlerType.Fault)
{
if (footerIndex >= graph.IndexOf(eh.HandlerStart) &&
footerIndex < graph.IndexOf(eh.HandlerEnd))
{
ehs.Add(eh);
}
}
}
ehMap[block] = ehs;
}
foreach (var eh in ehs)
{
uint ehVal;
if (finallyIds.TryGetValue(eh, out ehVal))
{
if (key.ExitState > ehVal)
{
finallyIds[eh] = key.ExitState;
updated = true;
}
else if (key.ExitState < ehVal)
{
key.ExitState = ehVal;
updated = true;
}
}
else
{
finallyIds[eh] = key.ExitState;
updated = true;
}
}
}
else if (block.Footer.OpCode.Code == Code.Leave || block.Footer.OpCode.Code == Code.Leave_S)
{
// Match the exit state with finally/fault/filter
List <ExceptionHandler> ehs;
if (!ehMap.TryGetValue(block, out ehs))
{
ehs = new List <ExceptionHandler>();
int footerIndex = graph.IndexOf(block.Footer);
foreach (var eh in graph.Body.ExceptionHandlers)
{
if (footerIndex >= graph.IndexOf(eh.TryStart) &&
footerIndex < graph.IndexOf(eh.TryEnd))
{
ehs.Add(eh);
}
}
ehMap[block] = ehs;
}
uint?maxVal = null;
foreach (var eh in ehs)
{
uint ehVal;
if (finallyIds.TryGetValue(eh, out ehVal) && (maxVal == null || ehVal > maxVal))
{
if (maxVal != null)
{
updated = true;
}
maxVal = ehVal;
}
}
if (maxVal != null)
{
if (key.ExitState > maxVal.Value)
{
maxVal = key.ExitState;
updated = true;
}
else if (key.ExitState < maxVal.Value)
{
key.ExitState = maxVal.Value;
updated = true;
}
foreach (var eh in ehs)
{
finallyIds[eh] = maxVal.Value;
}
}
}
keys[block.Id] = key;
}
} while (updated);
// Replace id with actual values
var idMap = new Dictionary <uint, uint>();
for (int i = 0; i < keys.Length; i++)
{
BlockKey key = keys[i];
uint entryId = key.EntryState;
if (!idMap.TryGetValue(entryId, out key.EntryState))
{
key.EntryState = idMap[entryId] = random.NextUInt32();
}
uint exitId = key.ExitState;
if (!idMap.TryGetValue(exitId, out key.ExitState))
{
key.ExitState = idMap[exitId] = random.NextUInt32();
}
keys[i] = key;
}
}
static void ProcessBlocks(BlockKey[] keys, ControlFlowGraph graph, RandomGenerator random) {
uint id = 0;
for (int i = 0; i < keys.Length; i++) {
keys[i].EntryState = id++;
keys[i].ExitState = id++;
}
var finallyIds = new Dictionary<ExceptionHandler, uint>();
var ehMap = new Dictionary<ControlFlowBlock, List<ExceptionHandler>>();
bool updated;
do {
updated = false;
// Update the state ids with the maximum id
foreach (ControlFlowBlock block in graph) {
BlockKey key = keys[block.Id];
if (block.Sources.Count > 0) {
uint newEntry = block.Sources.Select(b => keys[b.Id].ExitState).Max();
if (key.EntryState != newEntry) {
key.EntryState = newEntry;
updated = true;
}
}
if (block.Targets.Count > 0) {
uint newExit = block.Targets.Select(b => keys[b.Id].EntryState).Max();
if (key.ExitState != newExit) {
key.ExitState = newExit;
updated = true;
}
}
if (block.Footer.OpCode.Code == Code.Endfilter || block.Footer.OpCode.Code == Code.Endfinally) {
// Match the exit state within finally/fault/filter
List<ExceptionHandler> ehs;
if (!ehMap.TryGetValue(block, out ehs)) {
ehs = new List<ExceptionHandler>();
int footerIndex = graph.IndexOf(block.Footer);
foreach (var eh in graph.Body.ExceptionHandlers) {
if (eh.FilterStart != null && block.Footer.OpCode.Code == Code.Endfilter) {
if (footerIndex >= graph.IndexOf(eh.FilterStart) &&
footerIndex < graph.IndexOf(eh.HandlerStart))
ehs.Add(eh);
}
else if (eh.HandlerType == ExceptionHandlerType.Finally ||
eh.HandlerType == ExceptionHandlerType.Fault) {
if (footerIndex >= graph.IndexOf(eh.HandlerStart) &&
(eh.HandlerEnd == null || footerIndex < graph.IndexOf(eh.HandlerEnd)))
ehs.Add(eh);
}
}
ehMap[block] = ehs;
}
foreach (var eh in ehs) {
uint ehVal;
if (finallyIds.TryGetValue(eh, out ehVal)) {
if (key.ExitState > ehVal) {
finallyIds[eh] = key.ExitState;
updated = true;
}
else if (key.ExitState < ehVal) {
key.ExitState = ehVal;
updated = true;
}
}
else {
finallyIds[eh] = key.ExitState;
updated = true;
}
}
}
else if (block.Footer.OpCode.Code == Code.Leave || block.Footer.OpCode.Code == Code.Leave_S) {
// Match the exit state with finally/fault/filter
List<ExceptionHandler> ehs;
if (!ehMap.TryGetValue(block, out ehs)) {
ehs = new List<ExceptionHandler>();
int footerIndex = graph.IndexOf(block.Footer);
foreach (var eh in graph.Body.ExceptionHandlers) {
if (footerIndex >= graph.IndexOf(eh.TryStart) &&
(eh.TryEnd == null || footerIndex < graph.IndexOf(eh.TryEnd)))
ehs.Add(eh);
}
ehMap[block] = ehs;
}
uint? maxVal = null;
foreach (var eh in ehs) {
uint ehVal;
if (finallyIds.TryGetValue(eh, out ehVal) && (maxVal == null || ehVal > maxVal)) {
if (maxVal != null)
updated = true;
maxVal = ehVal;
}
}
if (maxVal != null) {
if (key.ExitState > maxVal.Value) {
maxVal = key.ExitState;
updated = true;
}
else if (key.ExitState < maxVal.Value) {
key.ExitState = maxVal.Value;
updated = true;
}
foreach (var eh in ehs)
finallyIds[eh] = maxVal.Value;
}
}
keys[block.Id] = key;
}
} while (updated);
if (random != null) {
// Replace id with actual values
var idMap = new Dictionary<uint, uint>();
for (int i = 0; i < keys.Length; i++) {
BlockKey key = keys[i];
uint entryId = key.EntryState;
if (!idMap.TryGetValue(entryId, out key.EntryState))
key.EntryState = idMap[entryId] = random.NextUInt32();
uint exitId = key.ExitState;
if (!idMap.TryGetValue(exitId, out key.ExitState))
key.ExitState = idMap[exitId] = random.NextUInt32();
keys[i] = key;
}
}
}