private static void Analyze(CSharpSyntaxNode declarationBody, ISymbol symbol,
Action <ExplodedGraph, SyntaxNodeAnalysisContext> analyze, SyntaxNodeAnalysisContext context)
{
if (declarationBody == null ||
declarationBody.ContainsDiagnostics)
{
return;
}
IControlFlowGraph cfg;
if (!ControlFlowGraph.TryGet(declarationBody, context.SemanticModel, out cfg))
{
return;
}
var lva = LiveVariableAnalysis.Analyze(cfg, symbol, context.SemanticModel);
var explodedGraph = new ExplodedGraph(cfg, symbol, context.SemanticModel, lva);
analyze(explodedGraph, context);
}
public void ExplodedGraph_BothBranchesVisited()
{
string testInput = "var a = false; bool b; if (inParameter) { b = inParameter; } else { b = !inParameter; } a = b;";
SemanticModel semanticModel;
var method = ControlFlowGraphTest.CompileWithMethodBody(string.Format(TestInput, testInput), "Bar", out semanticModel);
var methodSymbol = semanticModel.GetDeclaredSymbol(method);
var varDeclarators = method.DescendantNodes().OfType <VariableDeclaratorSyntax>();
var aSymbol = semanticModel.GetDeclaredSymbol(varDeclarators.First(d => d.Identifier.ToString() == "a"));
var bSymbol = semanticModel.GetDeclaredSymbol(varDeclarators.First(d => d.Identifier.ToString() == "b"));
var parameters = method.DescendantNodes().OfType <ParameterSyntax>();
var inParameterSymbol = semanticModel.GetDeclaredSymbol(parameters.First(d => d.Identifier.ToString() == "inParameter"));
var cfg = ControlFlowGraph.Create(method.Body, semanticModel);
var lva = LiveVariableAnalysis.Analyze(cfg, methodSymbol, semanticModel);
var explodedGraph = new ExplodedGraph(cfg, methodSymbol, semanticModel, lva);
var explorationEnded = false;
explodedGraph.ExplorationEnded += (sender, args) => { explorationEnded = true; };
var numberOfExitBlockReached = 0;
explodedGraph.ExitBlockReached += (sender, args) => { numberOfExitBlockReached++; };
var numberOfLastInstructionVisits = 0;
var numberOfProcessedInstructions = 0;
var visitedBlocks = new HashSet <Block>();
var branchesVisited = 0;
explodedGraph.InstructionProcessed +=
(sender, args) =>
{
visitedBlocks.Add(args.ProgramPoint.Block);
numberOfProcessedInstructions++;
if (args.Instruction.ToString() == "a = false")
{
branchesVisited++;
args.ProgramState.GetSymbolValue(aSymbol).Should().Be(SymbolicValue.False); // Roslyn is clever !true has const value.
}
if (args.Instruction.ToString() == "b = inParameter")
{
branchesVisited++;
bSymbol.HasConstraint(BoolConstraint.True, args.ProgramState).Should().BeTrue();
inParameterSymbol.HasConstraint(BoolConstraint.True, args.ProgramState).Should().BeTrue();
}
if (args.Instruction.ToString() == "b = !inParameter")
{
branchesVisited++;
// b has value, but not true or false
args.ProgramState.GetSymbolValue(bSymbol).Should().NotBeNull();
bSymbol.HasConstraint(BoolConstraint.False, args.ProgramState).Should().BeFalse();
bSymbol.HasConstraint(BoolConstraint.True, args.ProgramState).Should().BeFalse();
inParameterSymbol.HasConstraint(BoolConstraint.False, args.ProgramState).Should().BeTrue();
}
if (args.Instruction.ToString() == "a = b")
{
branchesVisited++;
args.ProgramState.GetSymbolValue(inParameterSymbol).Should().BeNull(); // not out/ref parameter and LVA says dead
numberOfLastInstructionVisits++;
}
};
explodedGraph.Walk();
explorationEnded.Should().BeTrue();
branchesVisited.Should().Be(4 + 1);
numberOfExitBlockReached.Should().Be(1,
"All variables are dead at the ExitBlock, so whenever we get there, the ExplodedGraph nodes should be the same, " +
"and thus should be processed only once.");
numberOfLastInstructionVisits.Should().Be(2);
visitedBlocks.Count.Should().Be(cfg.Blocks.Count() - 1 /* Exit block*/);
}
public void ExplodedGraph_NonDecisionMakingAssignments()
{
string testInput = "var a = true; a |= false; var b = 42; b++; ++b;";
SemanticModel semanticModel;
var method = ControlFlowGraphTest.Compile(string.Format(TestInput, testInput), "Bar", out semanticModel);
var methodSymbol = semanticModel.GetDeclaredSymbol(method);
var varDeclarators = method.DescendantNodes().OfType <VariableDeclaratorSyntax>();
var aSymbol = semanticModel.GetDeclaredSymbol(varDeclarators.First(d => d.Identifier.ToString() == "a"));
var bSymbol = semanticModel.GetDeclaredSymbol(varDeclarators.First(d => d.Identifier.ToString() == "b"));
var cfg = ControlFlowGraph.Create(method.Body, semanticModel);
var lva = LiveVariableAnalysis.Analyze(cfg, methodSymbol, semanticModel);
var explodedGraph = new ExplodedGraph(cfg, methodSymbol, semanticModel, lva);
SymbolicValue sv = null;
var numberOfProcessedInstructions = 0;
var branchesVisited = 0;
explodedGraph.InstructionProcessed +=
(sender, args) =>
{
numberOfProcessedInstructions++;
if (args.Instruction.ToString() == "a = true")
{
branchesVisited++;
Assert.IsTrue(args.ProgramState.GetSymbolValue(aSymbol) == SymbolicValue.True);
}
if (args.Instruction.ToString() == "a |= false")
{
branchesVisited++;
Assert.IsNotNull(args.ProgramState.GetSymbolValue(aSymbol));
Assert.IsFalse(args.ProgramState.GetSymbolValue(aSymbol) == SymbolicValue.False);
Assert.IsFalse(args.ProgramState.GetSymbolValue(aSymbol) == SymbolicValue.True);
}
if (args.Instruction.ToString() == "b = 42")
{
branchesVisited++;
sv = args.ProgramState.GetSymbolValue(bSymbol);
Assert.IsNotNull(sv);
}
if (args.Instruction.ToString() == "b++")
{
branchesVisited++;
var svNew = args.ProgramState.GetSymbolValue(bSymbol);
Assert.IsNotNull(svNew);
Assert.AreNotEqual(sv, svNew);
}
if (args.Instruction.ToString() == "++b")
{
branchesVisited++;
var svNew = args.ProgramState.GetSymbolValue(bSymbol);
Assert.IsNotNull(svNew);
Assert.AreNotEqual(sv, svNew);
}
};
explodedGraph.Walk();
Assert.AreEqual(11, numberOfProcessedInstructions);
Assert.AreEqual(5, branchesVisited);
}