LinkedList <Instruction[]> SpiltStatements(InstrBlock block, Trace trace, CFContext ctx)
{
var statements = new LinkedList <Instruction[]>();
var currentStatement = new List <Instruction>();
// Instructions that must be included in the ccurrent statement to ensure all outgoing
// branches have stack = 0
var requiredInstr = new HashSet <Instruction>();
for (int i = 0; i < block.Instructions.Count; i++)
{
Instruction instr = block.Instructions[i];
currentStatement.Add(instr);
bool shouldSpilt = i + 1 < block.Instructions.Count && trace.HasMultipleSources(block.Instructions[i + 1].Offset);
switch (instr.OpCode.FlowControl)
{
case FlowControl.Branch:
case FlowControl.Cond_Branch:
case FlowControl.Return:
case FlowControl.Throw:
shouldSpilt = true;
if (trace.AfterStack[instr.Offset] != 0)
{
if (instr.Operand is Instruction)
{
requiredInstr.Add((Instruction)instr.Operand);
}
else if (instr.Operand is Instruction[])
{
foreach (var target in (Instruction[])instr.Operand)
{
requiredInstr.Add(target);
}
}
}
break;
}
requiredInstr.Remove(instr);
if ((instr.OpCode.OpCodeType != OpCodeType.Prefix && trace.AfterStack[instr.Offset] == 0 &&
requiredInstr.Count == 0) &&
(shouldSpilt || ctx.Intensity > ctx.Random.NextDouble()))
{
statements.AddLast(currentStatement.ToArray());
currentStatement.Clear();
}
}
if (currentStatement.Count > 0)
{
statements.AddLast(currentStatement.ToArray());
}
return(statements);
}
LinkedList <Instruction[]> SpiltFragments(InstrBlock block, CFContext ctx)
{
var fragments = new LinkedList <Instruction[]>();
var currentFragment = new List <Instruction>();
int skipCount = -1;
for (int i = 0; i < block.Instructions.Count; i++)
{
if (skipCount != -1)
{
if (skipCount > 0)
{
currentFragment.Add(block.Instructions[i]);
skipCount--;
continue;
}
fragments.AddLast(currentFragment.ToArray());
currentFragment.Clear();
skipCount = -1;
}
if (block.Instructions[i].OpCode.OpCodeType == OpCodeType.Prefix)
{
skipCount = 1;
currentFragment.Add(block.Instructions[i]);
}
if (i + 2 < block.Instructions.Count &&
block.Instructions[i + 0].OpCode.Code == Code.Dup &&
block.Instructions[i + 1].OpCode.Code == Code.Ldvirtftn &&
block.Instructions[i + 2].OpCode.Code == Code.Newobj)
{
skipCount = 2;
currentFragment.Add(block.Instructions[i]);
}
if (i + 4 < block.Instructions.Count &&
block.Instructions[i + 0].OpCode.Code == Code.Ldc_I4 &&
block.Instructions[i + 1].OpCode.Code == Code.Newarr &&
block.Instructions[i + 2].OpCode.Code == Code.Dup &&
block.Instructions[i + 3].OpCode.Code == Code.Ldtoken &&
block.Instructions[i + 4].OpCode.Code == Code.Call) // Array initializer
{
skipCount = 4;
currentFragment.Add(block.Instructions[i]);
}
if (i + 1 < block.Instructions.Count &&
block.Instructions[i + 0].OpCode.Code == Code.Ldftn &&
block.Instructions[i + 1].OpCode.Code == Code.Newobj)
{
skipCount = 1;
currentFragment.Add(block.Instructions[i]);
}
currentFragment.Add(block.Instructions[i]);
if (ctx.Intensity > ctx.Random.NextDouble())
{
fragments.AddLast(currentFragment.ToArray());
currentFragment.Clear();
}
}
if (currentFragment.Count > 0)
{
fragments.AddLast(currentFragment.ToArray());
}
return(fragments);
}
public static ScopeBlock ParseBody(CilBody body)
{
var ehScopes = new Dictionary <ExceptionHandler, Tuple <ScopeBlock, ScopeBlock, ScopeBlock> >();
foreach (ExceptionHandler eh in body.ExceptionHandlers)
{
var tryBlock = new ScopeBlock(BlockType.Try, eh);
var handlerType = BlockType.Handler;
if (eh.HandlerType == ExceptionHandlerType.Finally)
{
handlerType = BlockType.Finally;
}
else if (eh.HandlerType == ExceptionHandlerType.Fault)
{
handlerType = BlockType.Fault;
}
var handlerBlock = new ScopeBlock(handlerType, eh);
if (eh.FilterStart != null)
{
var filterBlock = new ScopeBlock(BlockType.Filter, eh);
ehScopes[eh] = Tuple.Create(tryBlock, handlerBlock, filterBlock);
}
else
{
ehScopes[eh] = Tuple.Create(tryBlock, handlerBlock, (ScopeBlock)null);
}
}
var root = new ScopeBlock(BlockType.Normal, null);
var scopeStack = new Stack <ScopeBlock>();
scopeStack.Push(root);
foreach (Instruction instr in body.Instructions)
{
foreach (ExceptionHandler eh in body.ExceptionHandlers)
{
Tuple <ScopeBlock, ScopeBlock, ScopeBlock> ehScope = ehScopes[eh];
if (instr == eh.TryEnd)
{
scopeStack.Pop();
}
if (instr == eh.HandlerEnd)
{
scopeStack.Pop();
}
if (eh.FilterStart != null && instr == eh.HandlerStart)
{
// Filter must precede handler immediately
Debug.Assert(scopeStack.Peek().Type == BlockType.Filter);
scopeStack.Pop();
}
}
foreach (ExceptionHandler eh in body.ExceptionHandlers.Reverse())
{
Tuple <ScopeBlock, ScopeBlock, ScopeBlock> ehScope = ehScopes[eh];
ScopeBlock parent = scopeStack.Count > 0 ? scopeStack.Peek() : null;
if (instr == eh.TryStart)
{
if (parent != null)
{
parent.Children.Add(ehScope.Item1);
}
scopeStack.Push(ehScope.Item1);
}
if (instr == eh.HandlerStart)
{
if (parent != null)
{
parent.Children.Add(ehScope.Item2);
}
scopeStack.Push(ehScope.Item2);
}
if (instr == eh.FilterStart)
{
if (parent != null)
{
parent.Children.Add(ehScope.Item3);
}
scopeStack.Push(ehScope.Item3);
}
}
ScopeBlock scope = scopeStack.Peek();
var block = scope.Children.LastOrDefault() as InstrBlock;
if (block == null)
{
scope.Children.Add(block = new InstrBlock());
}
block.Instructions.Add(instr);
}
foreach (ExceptionHandler eh in body.ExceptionHandlers)
{
if (eh.TryEnd == null)
{
scopeStack.Pop();
}
if (eh.HandlerEnd == null)
{
scopeStack.Pop();
}
}
Debug.Assert(scopeStack.Count == 1);
return(root);
}
