public ILStructure(CilBody body)
: this(ILStructureType.Root, 0, body.GetCodeSize())
{
// Build the tree of exception structures:
for (int i = 0; i < body.ExceptionHandlers.Count; i++)
{
ExceptionHandler eh = body.ExceptionHandlers[i];
if (!body.ExceptionHandlers.Take(i).Any(oldEh => oldEh.TryStart == eh.TryStart && oldEh.TryEnd == eh.TryEnd))
{
AddNestedStructure(new ILStructure(ILStructureType.Try, (int)eh.TryStart.Offset, (int)eh.TryEnd.Offset, eh));
}
if (eh.HandlerType == ExceptionHandlerType.Filter)
{
AddNestedStructure(new ILStructure(ILStructureType.Filter, (int)eh.FilterStart.Offset, (int)eh.HandlerStart.Offset, eh));
}
AddNestedStructure(new ILStructure(ILStructureType.Handler, (int)eh.HandlerStart.Offset, eh.HandlerEnd == null ? body.GetCodeSize() : (int)eh.HandlerEnd.Offset, eh));
}
// Very simple loop detection: look for backward branches
List <KeyValuePair <Instruction, Instruction> > allBranches = FindAllBranches(body);
// We go through the branches in reverse so that we find the biggest possible loop boundary first (think loops with "continue;")
for (int i = allBranches.Count - 1; i >= 0; i--)
{
int loopEnd = allBranches[i].Key.GetEndOffset();
int loopStart = (int)allBranches[i].Value.Offset;
if (loopStart < loopEnd)
{
// We found a backward branch. This is a potential loop.
// Check that is has only one entry point:
Instruction entryPoint = null;
// entry point is first instruction in loop if prev inst isn't an unconditional branch
Instruction prev = body.GetPrevious(allBranches[i].Value);
if (prev != null && !OpCodeInfo.IsUnconditionalBranch(prev.OpCode))
{
entryPoint = allBranches[i].Value;
}
bool multipleEntryPoints = false;
foreach (var pair in allBranches)
{
if (pair.Key.Offset < loopStart || pair.Key.Offset >= loopEnd)
{
if (loopStart <= pair.Value.Offset && pair.Value.Offset < loopEnd)
{
// jump from outside the loop into the loop
if (entryPoint == null)
{
entryPoint = pair.Value;
}
else if (pair.Value != entryPoint)
{
multipleEntryPoints = true;
}
}
}
}
if (!multipleEntryPoints)
{
AddNestedStructure(new ILStructure(ILStructureType.Loop, loopStart, loopEnd, entryPoint));
}
}
}
SortChildren();
}
