private void AnalyzeBlockFrom(MethodDefinition method, Instruction instruction, IntervalCollection methodBlocks)
{
int nextIntervalStart;
var startingOffset = instruction.Offset;
// if our entry point can be found in some existing block
// we have to divide that block
if (methodBlocks.DivideIfNecessary(startingOffset, out nextIntervalStart))
{
return;
}
if (nextIntervalStart == -1)
{
nextIntervalStart = int.MaxValue;
}
while (NextInstructionShouldBeReached(instruction) &&
(instruction.Offset + instruction.GetSize()) < nextIntervalStart)
{
instruction = instruction.Next;
if (instruction == null)
{
throw new InvalidOperationException("Invalid IL code.");
}
}
var instructionSize = instruction.GetSize();
methodBlocks.Insert(startingOffset, instruction.Offset - startingOffset + instructionSize);
switch (instruction.OpCode.FlowControl)
{
case FlowControl.Return:
case FlowControl.Throw:
return;
case FlowControl.Branch:
AnalyzeBlockFrom(method, ((Instruction)instruction.Operand), methodBlocks);
break;
case FlowControl.Cond_Branch:
var operandAsInstruction = instruction.Operand as Instruction;
var operandAsInstructionArray = instruction.Operand as Instruction[];
if (operandAsInstruction != null)
{
AnalyzeBlockFrom(method, operandAsInstruction, methodBlocks);
}
else if (operandAsInstructionArray != null)
{
foreach (var operandInstruction in operandAsInstructionArray)
{
AnalyzeBlockFrom(method, operandInstruction, methodBlocks);
}
}
AnalyzeBlockFrom(method, instruction.Next, methodBlocks);
break;
case FlowControl.Break:
case FlowControl.Meta:
case FlowControl.Phi:
throw new NotImplementedException();
case FlowControl.Call:
case FlowControl.Next:
// we've reached here due to the nextIntervalStart that finished our scan prematurely
return;
}
}