public override void Mangle(ICFMangleContext context, Block.Regular block)
{
var fragments = context.SplitFragments(block);
if (fragments.Count < 4)
{
return;
}
var current = fragments.First;
while (current.Next != null)
{
var newFragment = new CilFragment(current.Value);
context.AddJump(newFragment, current.Next.Value.First, true);
current.Value = newFragment;
current = current.Next;
}
var first = fragments.First.Value;
fragments.RemoveFirst();
var last = fragments.Last.Value;
fragments.RemoveLast();
var newFragments = fragments.ToList();
newFragments.Shuffle(Mangler.Rng);
block.Fragment.Reset(first
.Concat(newFragments.SelectMany(fragment => fragment))
.Concat(last));
}
public void Mangle(Block.Regular block)
{
var rng = _switch.Mangler.Rng;
var fi = _context.RootBlock.FlowInfo.Info;
var fragments = _context.SplitFragments(block);
if (fragments.Count < 3)
{
return;
}
int i;
var keyId = Enumerable.Range(0, fragments.Count).ToArray();
keyId.Shuffle(rng);
var key = new int[keyId.Length];
for (i = 0; i < key.Length; i++)
{
var q = rng.NextInt32() & 0x7fffffff;
key[i] = q - q % fragments.Count + keyId[i];
}
var statementKeys = new Dictionary <Instruction, int>();
var current = fragments.First;
i = 0;
while (current != null)
{
if (i != 0)
{
statementKeys[current.Value.First] = key[i];
}
i++;
current = current.Next;
}
var lastInstructions = new HashSet <Instruction>(fragments.Select(f => f.Last()));
var blockInstructions = new HashSet <Instruction>(block.Fragment);
var firstFragmentInstructions = new HashSet <Instruction>(fragments.First());
bool HasUnknownSource(IEnumerable <Instruction> instrs) =>
instrs.Any(instr =>
{
//return true;
fi.TryGetValue(instr, out var info);
if (info.RefCount > 1)
{
return(true);
}
Debug.Assert(info.RefCount == 1);
var srcs = info.ReferencedBy;
if (srcs.Count == 0)
{
return(false);
}
Debug.Assert(srcs.Count == 1);
var src = srcs[0];
return
// Target of switch => assume unknown
(src.OpCode.Code == Code.Switch // Operand is Instruction[]
// Not targeted by the last of statements
|| lastInstructions.Contains(src)
// Not within current instruction block / targeted in first statement
// || src.Offset <= fragments.First.Value.Last().Offset || src.Offset >= block.Fragment.Last().Offset
|| !blockInstructions.Contains(src) ||
firstFragmentInstructions.Contains(src));
});
var switchInstr = new Instruction(OpCodes.Switch);
var switchHdr = new CilFragment();
if (_predicate != null)
{
switchHdr.Add(Instruction.CreateLdcI4(_predicate.GetSwitchKey(key[1])));
_predicate.EmitSwitchLoad(switchHdr);
}
else
{
switchHdr.Add(Instruction.CreateLdcI4(key[1]));
}
switchHdr.Add(Instruction.Create(OpCodes.Dup));
switchHdr.Add(Instruction.Create(OpCodes.Stloc, _local));
switchHdr.Add(Instruction.Create(OpCodes.Ldc_I4, fragments.Count));
switchHdr.Add(Instruction.Create(OpCodes.Rem_Un));
switchHdr.Add(switchInstr);
_context.AddJump(switchHdr, fragments.Last.Value.First, true);
var switchHdrSecond = switchHdr.Instructions[1];
var operands = new Instruction[fragments.Count];
current = fragments.First;
i = 0;
while (current.Next != null)
{
var newFragment = new CilFragment(current.Value);
if (i != 0)
{
var lastInstr = newFragment.Last();
// Convert to switch
var converted = false;
fi.TryGetValue(lastInstr, out var info);
if (lastInstr.IsBr())
{
// Unconditional
var target = (Instruction)lastInstr.Operand;
if (info.ReferencedBy.Count == 0 && statementKeys.TryGetValue(target, out var brKey))
{
var targetKey = _predicate?.GetSwitchKey(brKey) ?? brKey;
var unkSrc = HasUnknownSource(newFragment);
newFragment.Instructions.RemoveAt(newFragment.Instructions.Count - 1);
if (unkSrc)
{
newFragment.Add(Instruction.Create(OpCodes.Ldc_I4, targetKey));
}
else
{
var thisKey = key[i];
var r = rng.NextInt32();
newFragment.Add(Instruction.Create(OpCodes.Ldloc, _local));
newFragment.Add(Instruction.CreateLdcI4(r));
newFragment.Add(Instruction.Create(OpCodes.Mul));
newFragment.Add(Instruction.Create(OpCodes.Ldc_I4, (thisKey * r) ^ targetKey));
newFragment.Add(Instruction.Create(OpCodes.Xor));
}
_context.AddJump(newFragment, switchHdrSecond, false);
operands[keyId[i]] = newFragment.First;
converted = true;
}
}
else if (lastInstr.IsConditionalBranch())
{
// Conditional
var target = (Instruction)lastInstr.Operand;
if (info.ReferencedBy.Count == 0 && statementKeys.TryGetValue(target, out var brKey))
{
var unkSrc = HasUnknownSource(newFragment);
var nextKey = key[i + 1];
var condBr = newFragment.Last().OpCode;
newFragment.Instructions.RemoveAt(newFragment.Instructions.Count - 1);
if (rng.NextBoolean())
{
condBr = DnextFactory.InverseBranch(condBr);
var tmp = brKey;
brKey = nextKey;
nextKey = tmp;
}
var thisKey = key[i];
int r = 0, xorKey = 0;
if (!unkSrc)
{
r = rng.NextInt32();
xorKey = thisKey * r;
}
var brKeyInstr =
Instruction.CreateLdcI4(xorKey ^ (_predicate?.GetSwitchKey(brKey) ?? brKey));
var nextKeyInstr =
Instruction.CreateLdcI4(xorKey ^ (_predicate?.GetSwitchKey(nextKey) ?? nextKey));
var pop = Instruction.Create(OpCodes.Pop);
newFragment.Add(Instruction.Create(condBr, brKeyInstr));
newFragment.Add(nextKeyInstr);
newFragment.Add(Instruction.Create(OpCodes.Dup));
newFragment.Add(Instruction.Create(OpCodes.Br, pop));
newFragment.Add(brKeyInstr);
newFragment.Add(Instruction.Create(OpCodes.Dup));
newFragment.Add(pop);
if (!unkSrc)
{
newFragment.Add(Instruction.Create(OpCodes.Ldloc, _local));
newFragment.Add(Instruction.CreateLdcI4(r));
newFragment.Add(Instruction.Create(OpCodes.Mul));
newFragment.Add(Instruction.Create(OpCodes.Xor));
}
_context.AddJump(newFragment, switchHdrSecond, false);
operands[keyId[i]] = newFragment.First;
converted = true;
}
}
if (!converted)
{
// Normal
var targetKey = _predicate?.GetSwitchKey(key[i + 1]) ?? key[i + 1];
if (!HasUnknownSource(newFragment))
{
var thisKey = key[i];
var r = rng.NextInt32();
newFragment.Add(Instruction.Create(OpCodes.Ldloc, _local));
newFragment.Add(Instruction.CreateLdcI4(r));
newFragment.Add(Instruction.Create(OpCodes.Mul));
newFragment.Add(Instruction.Create(OpCodes.Ldc_I4, (thisKey * r) ^ targetKey));
newFragment.Add(Instruction.Create(OpCodes.Xor));
}
else
{
newFragment.Add(Instruction.Create(OpCodes.Ldc_I4, targetKey));
}
_context.AddJump(newFragment, switchHdrSecond, false);
operands[keyId[i]] = newFragment.First;
}
}
else
{
operands[keyId[i]] = switchHdr.First;
}
current.Value = newFragment;
current = current.Next;
i++;
}
operands[keyId[i]] = current.Value.First;
switchInstr.Operand = operands;
var first = fragments.First.Value;
fragments.RemoveFirst();
var last = fragments.Last.Value;
fragments.RemoveLast();
var newStatements = fragments.ToList();
newStatements.Shuffle(rng);
block.Fragment.Reset(first.Concat(switchHdr).Concat(newStatements.SelectMany(s => s)).Concat(last));
}
