public virtual Instruction GetLastInstruction()
{
if (seq.IsEmpty())
{
return(null);
}
else
{
return(seq.GetLastInstr());
}
}
public static void MergeBasicBlocks(ControlFlowGraph graph)
{
while (true)
{
bool merged = false;
foreach (BasicBlock block in graph.GetBlocks())
{
InstructionSequence seq = block.GetSeq();
if (block.GetSuccs().Count == 1)
{
BasicBlock next = block.GetSuccs()[0];
if (next != graph.GetLast() && (seq.IsEmpty() || seq.GetLastInstr().group != ICodeConstants
.Group_Switch))
{
if (next.GetPreds().Count == 1 && (next.GetPredExceptions().Count == 0) && next !=
graph.GetFirst())
{
// TODO: implement a dummy start block
bool sameRanges = true;
foreach (ExceptionRangeCFG range in graph.GetExceptions())
{
if (range.GetProtectedRange().Contains(block) ^ range.GetProtectedRange().Contains
(next))
{
sameRanges = false;
break;
}
}
if (sameRanges)
{
seq.AddSequence(next.GetSeq());
Sharpen.Collections.AddAll(block.GetInstrOldOffsets(), next.GetInstrOldOffsets());
next.GetSeq().Clear();
RemoveEmptyBlock(graph, next, true);
merged = true;
break;
}
}
}
}
}
if (!merged)
{
break;
}
}
}
public static void ExtendSynchronizedRangeToMonitorexit(ControlFlowGraph graph)
{
while (true)
{
bool range_extended = false;
foreach (ExceptionRangeCFG range in graph.GetExceptions())
{
HashSet <BasicBlock> setPreds = new HashSet <BasicBlock>();
foreach (BasicBlock block in range.GetProtectedRange())
{
Sharpen.Collections.AddAll(setPreds, block.GetPreds());
}
setPreds.ExceptWith(range.GetProtectedRange());
if (setPreds.Count != 1)
{
continue;
}
// multiple predecessors, obfuscated range
var setPredsEnumerator = new EnumeratorAdapter <BasicBlock>(setPreds.GetEnumerator());
BasicBlock predBlock = setPredsEnumerator.Next();
InstructionSequence predSeq = predBlock.GetSeq();
if (predSeq.IsEmpty() || predSeq.GetLastInstr().opcode != ICodeConstants.opc_monitorenter)
{
continue;
}
// not a synchronized range
bool monitorexit_in_range = false;
HashSet <BasicBlock> setProtectedBlocks = new HashSet <BasicBlock>();
Sharpen.Collections.AddAll(setProtectedBlocks, range.GetProtectedRange());
setProtectedBlocks.Add(range.GetHandler());
foreach (BasicBlock block in setProtectedBlocks)
{
InstructionSequence blockSeq = block.GetSeq();
for (int i = 0; i < blockSeq.Length(); i++)
{
if (blockSeq.GetInstr(i).opcode == ICodeConstants.opc_monitorexit)
{
monitorexit_in_range = true;
break;
}
}
if (monitorexit_in_range)
{
break;
}
}
if (monitorexit_in_range)
{
continue;
}
// protected range already contains monitorexit
HashSet <BasicBlock> setSuccs = new HashSet <BasicBlock>();
foreach (BasicBlock block in range.GetProtectedRange())
{
Sharpen.Collections.AddAll(setSuccs, block.GetSuccs());
}
setSuccs.ExceptWith(range.GetProtectedRange());
if (setSuccs.Count != 1)
{
continue;
}
// non-unique successor
BasicBlock succBlock = new Sharpen.EnumeratorAdapter <BasicBlock>(setSuccs.GetEnumerator()).Next();
InstructionSequence succSeq = succBlock.GetSeq();
int succ_monitorexit_index = -1;
for (int i = 0; i < succSeq.Length(); i++)
{
if (succSeq.GetInstr(i).opcode == ICodeConstants.opc_monitorexit)
{
succ_monitorexit_index = i;
break;
}
}
if (succ_monitorexit_index < 0)
{
continue;
}
// monitorexit not found in the single successor block
BasicBlock handlerBlock = range.GetHandler();
if (handlerBlock.GetSuccs().Count != 1)
{
continue;
}
// non-unique handler successor
BasicBlock succHandler = handlerBlock.GetSuccs()[0];
InstructionSequence succHandlerSeq = succHandler.GetSeq();
if (succHandlerSeq.IsEmpty() || succHandlerSeq.GetLastInstr().opcode != ICodeConstants
.opc_athrow)
{
continue;
}
// not a standard synchronized range
int handler_monitorexit_index = -1;
for (int i = 0; i < succHandlerSeq.Length(); i++)
{
if (succHandlerSeq.GetInstr(i).opcode == ICodeConstants.opc_monitorexit)
{
handler_monitorexit_index = i;
break;
}
}
if (handler_monitorexit_index < 0)
{
continue;
}
// monitorexit not found in the handler successor block
// checks successful, prerequisites satisfied, now extend the range
if (succ_monitorexit_index < succSeq.Length() - 1)
{
// split block
SimpleInstructionSequence seq = new SimpleInstructionSequence();
for (int counter = 0; counter < succ_monitorexit_index; counter++)
{
seq.AddInstruction(succSeq.GetInstr(0), -1);
succSeq.RemoveInstruction(0);
}
// build a separate block
BasicBlock newblock = new BasicBlock(++graph.last_id);
newblock.SetSeq(seq);
// insert new block
foreach (BasicBlock block in succBlock.GetPreds())
{
block.ReplaceSuccessor(succBlock, newblock);
}
newblock.AddSuccessor(succBlock);
graph.GetBlocks().AddWithKey(newblock, newblock.id);
succBlock = newblock;
}
// copy exception edges and extend protected ranges (successor block)
BasicBlock rangeExitBlock = succBlock.GetPreds()[0];
for (int j = 0; j < rangeExitBlock.GetSuccExceptions().Count; j++)
{
BasicBlock hd = rangeExitBlock.GetSuccExceptions()[j];
succBlock.AddSuccessorException(hd);
ExceptionRangeCFG rng = graph.GetExceptionRange(hd, rangeExitBlock);
rng.GetProtectedRange().Add(succBlock);
}
// copy instructions (handler successor block)
InstructionSequence handlerSeq = handlerBlock.GetSeq();
for (int counter = 0; counter < handler_monitorexit_index; counter++)
{
handlerSeq.AddInstruction(succHandlerSeq.GetInstr(0), -1);
succHandlerSeq.RemoveInstruction(0);
}
range_extended = true;
break;
}
if (!range_extended)
{
break;
}
}
}
