public void Prune(LiveVariablesAnalysis liveVariables)
{
foreach (var node in cfg.Nodes)
{
var result = liveVariables.Result[node.Id];
var input = result.Input.ToSet();
var phiInstructions = node.Instructions.OfType <PhiInstruction>().ToArray();
foreach (var phi in phiInstructions)
{
var isLive = input.Contains(phi.Result);
if (!isLive && phi.Result is DerivedVariable)
{
var derived = phi.Result as DerivedVariable;
isLive = input.Contains(derived.Original);
}
if (!isLive)
{
// TODO: Also remove phi instructions from method's body instructions collection.
node.Instructions.Remove(phi);
}
}
}
}
//string _code = String.Empty;
/// <summary>
/// For a given methodDefinition, create a CFG and run basic analyses such as
/// stack removal, SSA transformation, live-variables analysis, and copy-propagation.
/// </summary>
/// <param name="methodDefinition"></param>
/// <returns></returns>
private ControlFlowGraph PrepareMethod(IMethodDefinition methodDefinition)
{
var disassembler = new Disassembler(mhost, methodDefinition, sourceLocationProvider);
var methodBody = disassembler.Execute();
var cfg = ControlFlowGraph.GenerateNormalControlFlow(methodBody);
ControlFlowGraph.ComputeDominators(cfg);
ControlFlowGraph.IdentifyLoops(cfg);
ControlFlowGraph.ComputeDominatorTree(cfg);
ControlFlowGraph.ComputeDominanceFrontiers(cfg);
// Uniquely rename stack variables.
var splitter = new WebAnalysis(cfg);
splitter.Analyze();
splitter.Transform();
methodBody.UpdateVariables();
// Infer types for stack variables.
var typeAnalysis = new TypeInferenceAnalysis(cfg);
typeAnalysis.Analyze();
var backwardCopyAnalysis = new BackwardCopyPropagationAnalysis(cfg);
backwardCopyAnalysis.Analyze();
backwardCopyAnalysis.Transform(methodBody);
var lva = new LiveVariablesAnalysis(cfg);
lva.Analyze();
var ssa = new StaticSingleAssignmentAnalysis(methodBody, cfg);
ssa.Transform();
ssa.Prune(lva);
methodBody.UpdateVariables();
//_code = methodBody.ToString();
return(cfg);
}
public static void RunLiveVariableAnalysisExample()
{
string liveVariableExample = CompileLiveVariableAnalysisExample();
using (var host = new PeReader.DefaultHost())
using (var assembly = new Assembly(host))
{
// load binaries that are gonna be analyzed
Types.Initialize(host);
assembly.Load(liveVariableExample);
// search for the method definition in the assembly
// if you inspect this method definitions they are defined using the .NET IL instructions (aka bytecode)
var allDefinedMethodsInAssembly = assembly.Module.GetAllTypes() // get all defined types in the assembly (these are cci objects)
.SelectMany(typeDefinition => typeDefinition.Methods); /// get all defined methods (these are cci objects)
var targetMethod = allDefinedMethodsInAssembly.Where(m => m.Name.Value.Contains("Example")).First();
// transform it into a typed stackless three addres code representation
// this is a result of analysis-net framework
ControlFlowGraph cfg = null;
MethodBody methodBody = Transformations.ThreeAddressCode(targetMethod, host, out cfg);
// on top of the three address representation we apply a live variable analysis
// it is far easier to implement such analysis on this representation
// if you intent to apply it on top of the IL bytecode, you will have to guess what you have in the stack for each instruction
LiveVariablesAnalysis liveVariables = new LiveVariablesAnalysis(cfg);
liveVariables.Analyze();
// the result is the subset of live variables for each basic block in the cfg
DataFlowAnalysisResult <Backend.Utils.Subset <IVariable> >[] result = liveVariables.Result;
// export results
// it generates two files in the same directory as the executable:
// 1) cfg.dot contains a .dot representation of the control flow graph
// 2) live_variable_analysis.txt plain text representation of the live variable analysis
Export.ExportExample(cfg, result);
}
}
public void GenerateSSA(MethodDefinition method)
{
var methodInfo = programInfo.GetOrAdd(method);
//GenerateIL(method);
//GenerateTAC(method);
//GenerateCFG(method);
GenerateWebs(method);
if (!methodInfo.Contains("SSA_TEXT"))
{
var cfg = methodInfo.Get <ControlFlowGraph>("CFG");
// Live Variables
var liveVariables = new LiveVariablesAnalysis(cfg);
var livenessInfo = liveVariables.Analyze();
// SSA
var ssa = new StaticSingleAssignment(method.Body, cfg);
ssa.Transform();
ssa.Prune(livenessInfo);
method.Body.UpdateVariables();
var text = method.Body.ToString();
methodInfo.Add("SSA_TEXT", text);
text = DGMLSerializer.Serialize(cfg);
methodInfo.Set("CFG_TEXT", text);
text = DGMLSerializer.SerializeDominanceTree(cfg);
methodInfo.Set("DT_TEXT", text);
text = DGMLSerializer.SerializePostDominanceTree(cfg);
methodInfo.Set("PDT_TEXT", text);
text = DGMLSerializer.SerializeControlDependenceGraph(cfg);
methodInfo.Set("CDG_TEXT", text);
}
}
//string _code = String.Empty;
/// <summary>
/// For a given methodDefinition, create a CFG and run basic analyses such as
/// stack removal, SSA transformation, live-variables analysis, and copy-propagation.
/// </summary>
/// <param name="methodDefinition"></param>
/// <returns></returns>
private ControlFlowGraph PrepareMethod(IMethodDefinition methodDefinition)
{
var sw2 = new Stopwatch();
sw2.Start();
var disassembler = new Disassembler(mhost, methodDefinition, sourceLocationProvider);
var methodBody = disassembler.Execute();
var cfAnalysis = new ControlFlowAnalysis(methodBody);
var cfg = cfAnalysis.GenerateNormalControlFlow();
var domAnalysis = new DominanceAnalysis(cfg);
domAnalysis.Analyze();
domAnalysis.GenerateDominanceTree();
var loopAnalysis = new NaturalLoopAnalysis(cfg);
loopAnalysis.Analyze();
var domFrontierAnalysis = new DominanceFrontierAnalysis(cfg);
domFrontierAnalysis.Analyze();
var splitter = new WebAnalysis(cfg, methodDefinition);
splitter.Analyze();
splitter.Transform();
methodBody.UpdateVariables();
var analysis = new TypeInferenceAnalysis(cfg, methodBody.MethodDefinition.Type);
analysis.Analyze();
var copyProgapagtion = new ForwardCopyPropagationAnalysis(cfg);
copyProgapagtion.Analyze();
copyProgapagtion.Transform(methodBody);
var backwardCopyProgapagtion = new BackwardCopyPropagationAnalysis(cfg);
backwardCopyProgapagtion.Analyze();
backwardCopyProgapagtion.Transform(methodBody);
var liveVariables = new LiveVariablesAnalysis(cfg);
var resultLiveVar = liveVariables.Analyze();
var ssa = new StaticSingleAssignment(methodBody, cfg);
ssa.Transform();
ssa.Prune(liveVariables);
methodBody.UpdateVariables();
sw2.Stop();
this.nonAnalysisOverhead = sw2.Elapsed;
return(cfg);
//var cfg = ControlFlowGraph.GenerateNormalControlFlow(methodBody);
//ControlFlowGraph.ComputeDominators(cfg);
//ControlFlowGraph.IdentifyLoops(cfg);
//ControlFlowGraph.ComputeDominatorTree(cfg);
//ControlFlowGraph.ComputeDominanceFrontiers(cfg);
//// Uniquely rename stack variables.
//var splitter = new WebAnalysis(cfg);
//splitter.Analyze();
//splitter.Transform();
//methodBody.UpdateVariables();
//// Infer types for stack variables.
//var typeAnalysis = new TypeInferenceAnalysis(cfg);
//typeAnalysis.Analyze();
//var backwardCopyAnalysis = new BackwardCopyPropagationAnalysis(cfg);
//backwardCopyAnalysis.Analyze();
//backwardCopyAnalysis.Transform(methodBody);
//var lva = new LiveVariablesAnalysis(cfg);
//lva.Analyze();
//var ssa = new StaticSingleAssignmentAnalysis(methodBody, cfg);
//ssa.Transform();
//ssa.Prune(lva);
//methodBody.UpdateVariables();
////_code = methodBody.ToString();
//return cfg;
}
public MethodCfgAndTac AnalyzeIntraProcedural(IMethodDefinition methodDefinition)
{
// System.Console.WriteLine("Traversing: {0}", methodDefinition.GetName());
if (Stubber.SuppressM(methodDefinition))
{
return(null);
}
if (methodDefinition.IsExternal)
{
return(null);
}
if (methodDefinition.IsAbstract)
{
return(null);
}
ITypeDefinition containingDefn = methodDefinition.ContainingTypeDefinition;
ISourceLocationProvider sourceLocationProvider = null;
if (containingDefn != null)
{
IModule mod = TypeHelper.GetDefiningUnit(containingDefn) as IModule;
if (moduleToPdbMap.ContainsKey(mod))
{
sourceLocationProvider = moduleToPdbMap[mod];
}
else
{
if (!(mod == null || mod == Dummy.Module || mod == Dummy.Assembly))
{
sourceLocationProvider = GetPdbReader(mod.Location);
moduleToPdbMap[mod] = sourceLocationProvider;
}
}
}
var disassembler = new Disassembler(host, methodDefinition, sourceLocationProvider);
var methodBody = disassembler.Execute();
var cfAnalysis = new ControlFlowAnalysis(methodBody);
// var cfg = cfAnalysis.GenerateNormalControlFlow();
var cfg = cfAnalysis.GenerateExceptionalControlFlow();
var domAnalysis = new DominanceAnalysis(cfg);
domAnalysis.Analyze();
domAnalysis.GenerateDominanceTree();
var loopAnalysis = new NaturalLoopAnalysis(cfg);
loopAnalysis.Analyze();
var domFrontierAnalysis = new DominanceFrontierAnalysis(cfg);
domFrontierAnalysis.Analyze();
var splitter = new WebAnalysis(cfg, methodDefinition);
splitter.Analyze();
splitter.Transform();
methodBody.UpdateVariables();
var typeAnalysis = new TypeInferenceAnalysis(cfg, methodDefinition.Type);
typeAnalysis.Analyze();
var forwardCopyAnalysis = new ForwardCopyPropagationAnalysis(cfg);
forwardCopyAnalysis.Analyze();
forwardCopyAnalysis.Transform(methodBody);
// backwardCopyAnalysis is buggy - it says so in the source file - see notes in src/test
// var backwardCopyAnalysis = new BackwardCopyPropagationAnalysis(cfg);
// backwardCopyAnalysis.Analyze();
// backwardCopyAnalysis.Transform(methodBody);
var liveVariables = new LiveVariablesAnalysis(cfg);
liveVariables.Analyze();
var ssa = new StaticSingleAssignment(methodBody, cfg);
ssa.Transform();
ssa.Prune(liveVariables);
methodBody.UpdateVariables();
MethodCfgAndTac mct = new MethodCfgAndTac(cfg, methodBody);
foreach (IExceptionHandlerBlock ehInfo in disassembler.GetExceptionHandlers())
{
if (ehInfo is CatchExceptionHandler)
{
mct.ehInfoList.Add(ehInfo as CatchExceptionHandler);
}
}
return(mct);
}
public static ControlFlowGraph DoAnalysisPhases(this IMethodDefinition method, IMetadataHost host, ISourceLocationProvider locationProvider,
IEnumerable <IMethodReference> methodsToTryToInline = null)
{
AnalysisStats.extraAnalysisOverHead.Start();
var disassembler = new Disassembler(host, method, locationProvider);
var methodBody = disassembler.Execute();
MethodBodyProvider.Instance.AddBody(method, methodBody);
if (methodsToTryToInline != null)
{
DoInlining(method, host, methodBody, locationProvider, methodsToTryToInline);
}
var cfAnalysis = new ControlFlowAnalysis(methodBody);
//var cfg = cfAnalysis.GenerateExceptionalControlFlow();
var cfg = cfAnalysis.GenerateNormalControlFlow();
var domAnalysis = new DominanceAnalysis(cfg);
domAnalysis.Analyze();
domAnalysis.GenerateDominanceTree();
var loopAnalysis = new NaturalLoopAnalysis(cfg);
loopAnalysis.Analyze();
var domFrontierAnalysis = new DominanceFrontierAnalysis(cfg);
domFrontierAnalysis.Analyze();
var splitter = new WebAnalysis(cfg, method);
splitter.Analyze();
splitter.Transform();
methodBody.UpdateVariables();
var analysis = new TypeInferenceAnalysis(cfg, methodBody.MethodDefinition.Type);
analysis.Analyze();
var copyProgapagtion = new ForwardCopyPropagationAnalysis(cfg);
copyProgapagtion.Analyze();
copyProgapagtion.Transform(methodBody);
//var backwardCopyProgapagtion = new BackwardCopyPropagationAnalysis(cfg);
//backwardCopyProgapagtion.Analyze();
//backwardCopyProgapagtion.Transform(methodBody);
var liveVariables = new LiveVariablesAnalysis(cfg);
var resultLiveVar = liveVariables.Analyze();
var ssa = new StaticSingleAssignment(methodBody, cfg);
ssa.Transform();
ssa.Prune(liveVariables);
methodBody.UpdateVariables();
AnalysisStats.extraAnalysisOverHead.Stop();
return(cfg);
}
