public override void TraverseChildren(IBlockStatement block) {
base.TraverseChildren(block);
Contract.Assume(block is BlockStatement);
var decompiledBlock = (BlockStatement)block;
var statements = decompiledBlock.Statements;
for (int i = 0; i < statements.Count-1; i++) {
var switchInstruction = statements[i] as SwitchInstruction;
if (switchInstruction == null) continue;
SwitchStatement result = new SwitchStatement();
result.Expression = switchInstruction.switchExpression;
statements[i] = result;
for (int j = 0, n = switchInstruction.SwitchCases.Count; j < n; j++) {
CompileTimeConstant caseLabel = new CompileTimeConstant() { Value = j, Type = this.host.PlatformType.SystemInt32 };
var gotoCaseBody = switchInstruction.SwitchCases[j];
Contract.Assume(gotoCaseBody != null);
SwitchCase currentCase = new SwitchCase() { Expression = caseLabel };
result.Cases.Add(currentCase);
if (j < n-1) {
Contract.Assume(switchInstruction.SwitchCases[j+1] != null);
if (gotoCaseBody.TargetStatement == switchInstruction.SwitchCases[j+1].TargetStatement) continue;
}
currentCase.Body.Add(gotoCaseBody);
}
if (i == statements.Count-1) return;
Contract.Assert(i+1 <= statements.Count);
var gotoStatement = statements[i+1] as IGotoStatement;
if (gotoStatement != null) {
SwitchCase defaultCase = new SwitchCase() { }; // Default case is represented by a dummy Expression.
defaultCase.Body.Add(statements[i + 1]);
statements.RemoveAt(i + 1);
result.Cases.Add(defaultCase);
}
}
}
/// <summary>
/// Visits the specified switch statement.
/// </summary>
/// <param name="switchStatement">The switch statement.</param>
public override void Visit(ISwitchStatement switchStatement)
{
SwitchStatement mutableSwitchStatement = new SwitchStatement(switchStatement);
this.resultStatement = this.myCodeCopier.DeepCopy(mutableSwitchStatement);
}
/// <summary>
/// Visits the specified switch statement.
/// </summary>
/// <param name="switchStatement">The switch statement.</param>
/// <returns></returns>
protected virtual IStatement DeepCopy(SwitchStatement switchStatement)
{
switchStatement.Expression = this.Substitute(switchStatement.Expression);
switchStatement.Cases = this.DeepCopy(switchStatement.Cases);
return switchStatement;
}
/// <summary>
/// Build the state machine.
///
/// We start from state 0. For each yield return, we assign a unique state, which we call continueing state. For a yield return
/// assigned with state x, we move the state machine from the previous state to x. Whenever we see a yield break, we transit
/// the state to -1.
///
/// When we return from state x, we jump to a label that is inserted right after the previous yield return (that is assigned with state x).
/// </summary>
private BlockStatement BuildStateMachine(IteratorClosureInformation iteratorClosure, BlockStatement oldBody, Dictionary<int, ILabeledStatement> stateEntries) {
// Switch on cases. StateEntries, which have been computed previously, map a state number (for initial and continuing states) to a label that has been inserted
// right after the associated yield return.
BlockStatement result = new BlockStatement();
var returnFalse = new ReturnStatement() { Expression = new CompileTimeConstant() { Value = false, Type = this.host.PlatformType.SystemBoolean } };
var returnFalseLabel = new LabeledStatement() { Label = this.host.NameTable.GetNameFor("return false"), Statement = returnFalse };
List<ISwitchCase> cases = new List<ISwitchCase>();
foreach (int i in stateEntries.Keys) {
SwitchCase c = new SwitchCase() {
Expression = new CompileTimeConstant() { Type = this.host.PlatformType.SystemInt32, Value = i },
Body = new List<IStatement>(),
};
c.Body.Add(new GotoStatement() { TargetStatement = stateEntries[i] });
cases.Add(c);
}
// Default case.
SwitchCase defaultCase = new SwitchCase();
defaultCase.Body.Add(new GotoStatement() { TargetStatement = returnFalseLabel });
cases.Add(defaultCase);
SwitchStatement switchStatement = new SwitchStatement() {
Cases = cases,
Expression = new BoundExpression() { Type = this.host.PlatformType.SystemInt32, Instance = new ThisReference(), Definition = iteratorClosure.StateFieldReference }
};
result.Statements.Add(switchStatement);
result.Statements.Add(oldBody);
result.Statements.Add(returnFalseLabel);
return result;
}
private void DecompileSwitch(List<IStatement> statements, int i)
{
if (i >= statements.Count-1) return;
SwitchInstruction/*?*/ switchInstruction = statements[i] as SwitchInstruction;
if (switchInstruction == null) return;
SwitchStatement result = new SwitchStatement();
result.Expression = switchInstruction.switchExpression;
statements[i] = result;
for (int j = 0, n = switchInstruction.switchCases.Count; j < n; j++) {
CompileTimeConstant caseLabel = new CompileTimeConstant() { Value = j, Type = this.platformType.SystemInt32 };
var gotoCaseBody = switchInstruction.switchCases[j];
SwitchCase currentCase = new SwitchCase() { Expression = caseLabel };
result.Cases.Add(currentCase);
if (j < n-1 && gotoCaseBody.TargetStatement == switchInstruction.switchCases[j+1].TargetStatement) continue;
currentCase.Body.Add(gotoCaseBody);
}
if (i == statements.Count-1) return;
var gotoStatement = statements[i+1] as IGotoStatement;
if (gotoStatement != null) {
SwitchCase defaultCase = new SwitchCase() { }; // Default case is represented by a dummy Expression.
defaultCase.Body.Add(statements[i + 1]);
statements.RemoveAt(i + 1);
result.Cases.Add(defaultCase);
}
}
/// <summary>
/// Rewrites the children of the given switch statement.
/// </summary>
public virtual void RewriteChildren(SwitchStatement switchStatement)
{
this.RewriteChildren((Statement)switchStatement);
switchStatement.Expression = this.Rewrite(switchStatement.Expression);
switchStatement.Cases = this.Rewrite(switchStatement.Cases);
}
/// <summary>
/// Visits the specified switch statement.
/// </summary>
/// <param name="switchStatement">The switch statement.</param>
public override void Visit(ISwitchStatement switchStatement)
{
SwitchStatement mutableSwitchStatement = switchStatement as SwitchStatement;
if (alwaysMakeACopy || mutableSwitchStatement == null) mutableSwitchStatement = new SwitchStatement(switchStatement);
this.resultStatement = this.myCodeMutator.Visit(mutableSwitchStatement);
}
/// <summary>
/// Visits the specified switch statement.
/// </summary>
/// <param name="switchStatement">The switch statement.</param>
/// <returns></returns>
public virtual IStatement Visit(SwitchStatement switchStatement)
{
switchStatement.Expression = Visit(switchStatement.Expression);
switchStatement.Cases = Visit(switchStatement.Cases);
return switchStatement;
}
