/// <summary>
/// Makes random conditional jump instruction + links basic blocks and sets RefVars
/// </summary>
/// <param name="nop">NoOperation instruction (will be made into ConditionalJump)</param>
/// <param name="condition">Type of condition</param>
/// <param name="target">Target basic block the control flow is transfered to, if the relation holds true.</param>
public static void RandomConditionalJump(Instruction nop, Instruction.ConditionType condition, BasicBlock target)
{
if (nop.statementType != Objects.Common.StatementType.NoOperation && nop.statementType != Objects.Common.StatementType.UnconditionalJump)
{
throw new ObfuscatorException("Only NoOperation and UnconditionalJump instructions can be modified to ConditionalJump!");
}
if (nop.parent == null || nop.parent.parent == null)
{
throw new ObfuscatorException("Instruction -> basic block -> function parent link is broken.");
}
if (nop.parent.parent != target.parent)
{
throw new ObfuscatorException("The instruction and the basic block should be contained in the same function.");
}
Variable var = FakeParameters.GetRandom(nop.parent.parent);
if (var.fixedMax.HasValue && var.fixedMax.Value > Common.GlobalMaxValue)
{
throw new ObfuscatorException("The fixedMax value is greated then the globally accepted maximum.");
}
if (var.fixedMin.HasValue && var.fixedMin.Value < Common.GlobalMinValue)
{
throw new ObfuscatorException("The fixedMin value is smaller then the globally accepted minimum.");
}
int right_value = 0;
Instruction.RelationalOperationType relop = Instruction.RelationalOperationType.Equals;
bool use_min_limit = false;
// Here we chose to use a FixedMin or FixedMax for logical relation
if (var.fixedMin.HasValue && var.fixedMax.HasValue)
{
use_min_limit = (bool)Randomizer.OneFromMany(true, false);
}
else if (var.fixedMin.HasValue)
{
use_min_limit = true;
}
if (use_min_limit) // FixedMin will be used
{
right_value = Randomizer.OneFromSectionWithDescendingProbability(var.fixedMin.Value, Common.GlobalMinValue + Common.LoopConditionalJumpMaxRange);
switch (condition)
{
case Instruction.ConditionType.AlwaysTrue:
relop = (Instruction.RelationalOperationType)Randomizer.OneFromMany(Instruction.RelationalOperationType.Greater,
Instruction.RelationalOperationType.GreaterOrEquals);
break;
case Instruction.ConditionType.AlwaysFalse:
relop = (Instruction.RelationalOperationType)Randomizer.OneFromMany(Instruction.RelationalOperationType.Smaller,
Instruction.RelationalOperationType.SmallerOrEquals);
break;
case Instruction.ConditionType.Random:
relop = (Instruction.RelationalOperationType)Randomizer.OneFromMany(Instruction.RelationalOperationType.Smaller,
Instruction.RelationalOperationType.SmallerOrEquals,
Instruction.RelationalOperationType.Greater,
Instruction.RelationalOperationType.GreaterOrEquals);
break;
default:
throw new ObfuscatorException("Unrecognized condition type.");
}
}
if (!use_min_limit) // FixedMax will be used
{
right_value = Randomizer.OneFromSectionWithDescendingProbability(var.fixedMax.Value, Common.GlobalMaxValue - Common.LoopConditionalJumpMaxRange);
switch (condition)
{
case Instruction.ConditionType.AlwaysTrue:
relop = (Instruction.RelationalOperationType)Randomizer.OneFromMany(Instruction.RelationalOperationType.Smaller,
Instruction.RelationalOperationType.SmallerOrEquals);
break;
case Instruction.ConditionType.AlwaysFalse:
relop = (Instruction.RelationalOperationType)Randomizer.OneFromMany(Instruction.RelationalOperationType.Greater,
Instruction.RelationalOperationType.GreaterOrEquals);
break;
case Instruction.ConditionType.Random:
relop = (Instruction.RelationalOperationType)Randomizer.OneFromMany(Instruction.RelationalOperationType.Smaller,
Instruction.RelationalOperationType.SmallerOrEquals,
Instruction.RelationalOperationType.Greater,
Instruction.RelationalOperationType.GreaterOrEquals);
break;
default:
throw new ObfuscatorException("Unrecognized condition type.");
}
}
MakeInstruction.ConditionalJump(nop, var, right_value, relop, target);
}