/// <summary>
/// Creates a deterministic or nondeterministic fault effect body.
/// </summary>
private BlockSyntax CreateBody(IMethodSymbol method, BlockSyntax originalBody, SyntaxNode baseEffect)
{
var lineAdjustedOriginalBody = originalBody.AppendLineDirective(-1).PrependLineDirective(originalBody.GetLineNumber());
var componentType = _typeLookup[method.ContainingType.BaseType.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat)];
var faultEffectType = _typeLookup[method.ContainingType.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat)];
var faults = _faults[componentType];
var baseStatements = !method.ReturnsVoid
? new[] { Syntax.ReturnStatement(baseEffect) }
: new[] { Syntax.ExpressionStatement(baseEffect), Syntax.ReturnStatement() };
IMethodSymbol methodSymbol;
BlockSyntax body = null;
if (_methodLookup.TryGetValue(method.OverriddenMethod.ToDisplayString(SymbolDisplayFormat.CSharpErrorMessageFormat), out methodSymbol))
{
var priorityFaults = faults.Where(fault => fault.GetPriority(Compilation) == method.ContainingType.GetPriority(Compilation)).ToArray();
var overridingEffects = priorityFaults.Where(f => f.GetMembers().OfType<IMethodSymbol>().Any(m => m.Overrides(methodSymbol))).ToArray();
var overrideCount = overridingEffects.Length;
if (overrideCount > 1)
{
var fieldName = _faultChoiceFields[Tuple.Create(methodSymbol, priorityFaults[0].GetPriority(Compilation))];
var effectIndex = Array.IndexOf(priorityFaults, faultEffectType);
var choiceField = Syntax.MemberAccessExpression(Syntax.ThisExpression(), fieldName);
var levelCondition = Syntax.ValueNotEqualsExpression(choiceField, Syntax.LiteralExpression(effectIndex));
var ifStatement = Syntax.IfStatement(levelCondition, baseStatements).NormalizeWhitespace().WithTrailingNewLines(1);
if (overridingEffects.Last().Equals(faultEffectType))
{
var levelChoiceVariable = "levelChoice".ToSynthesized();
var levelCountVariable = "levelCount".ToSynthesized();
var writer = new CodeWriter();
writer.AppendLine("unsafe");
writer.AppendBlockStatement(() =>
{
writer.AppendLine($"var {levelChoiceVariable} = stackalloc int[{overrideCount}];");
writer.AppendLine($"var {levelCountVariable} = 0;");
for (var i = 0; i < overrideCount; ++i)
{
var effectType = overridingEffects[i].ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
var index = Array.IndexOf(priorityFaults, overridingEffects[i]);
writer.AppendLine($"if ({_tryActivate}((({effectType})this).{"fault".ToSynthesized()}))");
writer.IncreaseIndent();
writer.AppendLine($"{levelChoiceVariable}[{levelCountVariable}++] = {index};");
writer.DecreaseIndent();
writer.NewLine();
}
writer.AppendLine($"{fieldName} = {levelCountVariable} == 0 ? - 1 : {levelChoiceVariable}[ChooseIndex({levelCountVariable})];");
});
var selectionStatement = SyntaxFactory.ParseStatement(writer.ToString());
body = SyntaxFactory.Block(selectionStatement, (StatementSyntax)ifStatement, lineAdjustedOriginalBody);
}
else
body = SyntaxFactory.Block((StatementSyntax)ifStatement, lineAdjustedOriginalBody);
}
}
if (body == null)
{
var writer = new CodeWriter();
writer.AppendLine($"if (!{_tryActivate}(this.{"fault".ToSynthesized()}))");
writer.AppendBlockStatement(() =>
{
// Optimization: If we're normalizing a non-void returning method without ref/out parameters and
// the fault effect simply returns a constant value of primitive type, we generate code to check whether the non-fault
// value for the case that the fault is not activated (which is always the first case) actually differs
// from the constant value returned by the fault effect when the fault is activated. If both values are
// the same, the activation of the fault will have no effect, so we can undo it, reducing the number
// of transitions that have to be checked
var signatureAllowsOptimization =
!method.ReturnsVoid && CanBeCompared(method.ReturnType) && method.Parameters.All(parameter => parameter.RefKind == RefKind.None);
var faultEffectReturn = originalBody.Statements.Count == 1 ? originalBody.Statements[0] as ReturnStatementSyntax : null;
var isConstantValue = faultEffectReturn != null && SemanticModel.GetConstantValue(faultEffectReturn.Expression).HasValue;
if (signatureAllowsOptimization && isConstantValue)
{
writer.AppendLine($"var {"tmp".ToSynthesized()} = {baseEffect.ToFullString()};");
writer.AppendLine($"if ({"tmp".ToSynthesized()} == {faultEffectReturn.Expression.ToFullString()})");
writer.AppendBlockStatement(() => { writer.AppendLine($"{_undoActivation}(this.{"fault".ToSynthesized()});"); });
writer.AppendLine($"return {"tmp".ToSynthesized()};");
}
else
{
foreach (var statement in baseStatements)
writer.AppendLine(statement.NormalizeWhitespace().ToFullString());
}
});
writer.NewLine();
body = SyntaxFactory.Block(SyntaxFactory.ParseStatement(writer.ToString()), lineAdjustedOriginalBody);
}
return body.PrependLineDirective(-1);
}
/// <summary>
/// Creates a deterministic or nondeterministic fault effect body.
/// </summary>
private BlockSyntax CreateBody(IMethodSymbol method, BlockSyntax originalBody, SyntaxNode baseEffect)
{
var lineAdjustedOriginalBody = originalBody.AppendLineDirective(-1).PrependLineDirective(originalBody.GetLineNumber());
var componentType = _typeLookup[method.ContainingType.BaseType.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat)];
var faultEffectType = _typeLookup[method.ContainingType.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat)];
var faults = _faults[componentType];
var baseStatements = !method.ReturnsVoid
? new[] { Syntax.ReturnStatement(baseEffect) }
: new[] { Syntax.ExpressionStatement(baseEffect), Syntax.ReturnStatement() };
IMethodSymbol methodSymbol;
BlockSyntax body = null;
if (_methodLookup.TryGetValue(method.OverriddenMethod.ToDisplayString(SymbolDisplayFormat.CSharpErrorMessageFormat), out methodSymbol))
{
var priorityFaults = faults.Where(fault => fault.GetPriority(Compilation) == method.ContainingType.GetPriority(Compilation)).ToArray();
var overridingEffects = priorityFaults.Where(f => f.GetMembers().OfType <IMethodSymbol>().Any(m => m.Overrides(methodSymbol))).ToArray();
var overrideCount = overridingEffects.Length;
if (overrideCount > 1)
{
var fieldName = _faultChoiceFields[Tuple.Create(methodSymbol, priorityFaults[0].GetPriority(Compilation))];
var effectIndex = Array.IndexOf(priorityFaults, faultEffectType);
var choiceField = Syntax.MemberAccessExpression(Syntax.ThisExpression(), fieldName);
var levelCondition = Syntax.ValueNotEqualsExpression(choiceField, Syntax.LiteralExpression(effectIndex));
var ifStatement = Syntax.IfStatement(levelCondition, baseStatements).NormalizeWhitespace().WithTrailingNewLines(1);
if (overridingEffects.Last().Equals(faultEffectType))
{
var levelChoiceVariable = "levelChoice".ToSynthesized();
var levelCountVariable = "levelCount".ToSynthesized();
var writer = new CodeWriter();
writer.AppendLine("unsafe");
writer.AppendBlockStatement(() =>
{
writer.AppendLine($"var {levelChoiceVariable} = stackalloc int[{overrideCount}];");
writer.AppendLine($"var {levelCountVariable} = 0;");
for (var i = 0; i < overrideCount; ++i)
{
var effectType = overridingEffects[i].ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
var index = Array.IndexOf(priorityFaults, overridingEffects[i]);
writer.AppendLine($"if ({_tryActivate}((({effectType})this).{"fault".ToSynthesized()}))");
writer.IncreaseIndent();
writer.AppendLine($"{levelChoiceVariable}[{levelCountVariable}++] = {index};");
writer.DecreaseIndent();
writer.NewLine();
}
writer.AppendLine($"{fieldName} = {levelCountVariable} == 0 ? - 1 : {levelChoiceVariable}[ChooseIndex({levelCountVariable})];");
});
var selectionStatement = SyntaxFactory.ParseStatement(writer.ToString());
body = SyntaxFactory.Block(selectionStatement, (StatementSyntax)ifStatement, lineAdjustedOriginalBody);
}
else
{
body = SyntaxFactory.Block((StatementSyntax)ifStatement, lineAdjustedOriginalBody);
}
}
}
if (body == null)
{
var writer = new CodeWriter();
writer.AppendLine($"if (!{_tryActivate}(this.{"fault".ToSynthesized()}))");
writer.AppendBlockStatement(() =>
{
// Optimization: If we're normalizing a non-void returning method without ref/out parameters and
// the fault effect simply returns a constant value of primitive type, we generate code to check whether the non-fault
// value for the case that the fault is not activated (which is always the first case) actually differs
// from the constant value returned by the fault effect when the fault is activated. If both values are
// the same, the activation of the fault will have no effect, so we can undo it, reducing the number
// of transitions that have to be checked
var signatureAllowsOptimization =
!method.ReturnsVoid && CanBeCompared(method.ReturnType) && method.Parameters.All(parameter => parameter.RefKind == RefKind.None);
var faultEffectReturn = originalBody.Statements.Count == 1 ? originalBody.Statements[0] as ReturnStatementSyntax : null;
var isConstantValue = faultEffectReturn != null && SemanticModel.GetConstantValue(faultEffectReturn.Expression).HasValue;
if (signatureAllowsOptimization && isConstantValue)
{
writer.AppendLine($"var {"tmp".ToSynthesized()} = {baseEffect.ToFullString()};");
writer.AppendLine($"if ({"tmp".ToSynthesized()} == {faultEffectReturn.Expression.ToFullString()})");
writer.AppendBlockStatement(() => { writer.AppendLine($"{_undoActivation}(this.{"fault".ToSynthesized()});"); });
writer.AppendLine($"return {"tmp".ToSynthesized()};");
}
else
{
foreach (var statement in baseStatements)
{
writer.AppendLine(statement.NormalizeWhitespace().ToFullString());
}
}
});
writer.NewLine();
body = SyntaxFactory.Block(SyntaxFactory.ParseStatement(writer.ToString()), lineAdjustedOriginalBody);
}
return(body.PrependLineDirective(-1));
}
