private Expression VisitYield(YieldExpression node)
{
var value = Visit(node.Value);
var block = new List <Expression>();
if (value == null)
{
// Yield break
block.Add(MakeAssign(_state, AstUtils.Constant(Finished)));
if (_inTryWithFinally)
{
block.Add(Expression.Assign(_gotoRouter, AstUtils.Constant(GotoRouterYielding)));
}
block.Add(Expression.Goto(_returnLabels.Peek()));
return(Expression.Block(block));
}
// Yield return
block.Add(MakeAssign(_current, value));
YieldMarker marker = GetYieldMarker(node);
block.Add(MakeAssign(_state, AstUtils.Constant(marker.State)));
if (_inTryWithFinally)
{
block.Add(Expression.Assign(_gotoRouter, AstUtils.Constant(GotoRouterYielding)));
}
block.Add(Expression.Goto(_returnLabels.Peek()));
block.Add(Expression.Label(marker.Label));
block.Add(Expression.Assign(_gotoRouter, AstUtils.Constant(GotoRouterNone)));
block.Add(Utils.Empty());
return(Expression.Block(block));
}
private YieldMarker GetYieldMarker(YieldExpression node)
{
YieldMarker result = new YieldMarker(_yields.Count + 1);
_yields.Add(result);
Debug.Assert(node.YieldMarker == -1);
return(result);
}
private SwitchExpression MakeYieldRouter(Type type, int start, int end, LabelTarget newTarget)
{
Debug.Assert(end > start);
var cases = new SwitchCase[end - start];
for (int i = start; i < end; i++)
{
YieldMarker y = _yields[i];
cases[i - start] = Expression.SwitchCase(Expression.Goto(y.Label, type), AstUtils.Constant(y.State));
// Any jumps from outer switch statements should go to the this
// router, not the original label (which they cannot legally jump to)
y.Label = newTarget;
}
return(Expression.Switch(_gotoRouter, Expression.Default(type), cases));
}
private YieldMarker GetYieldMarker(YieldExpression node)
{
YieldMarker result = new YieldMarker(_yields.Count + 1);
_yields.Add(result);
if (node.YieldMarker != -1)
{
if (_debugCookies == null)
{
_debugCookies = new List <int>(1);
_debugCookies.Add(Int32.MaxValue);
}
_debugCookies.Insert(result.State, node.YieldMarker);
}
else
{
_debugCookies?.Insert(result.State, Int32.MaxValue);
}
return(result);
}
private Expression VisitYield(YieldExpression node)
{
if (node.Target != _generator.Target)
{
throw new InvalidOperationException("yield and generator must have the same LabelTarget object");
}
var value = Visit(node.Value);
var block = new ReadOnlyCollectionBuilder <Expression>();
if (value == null)
{
// Yield break
block.Add(Expression.Assign(_state, AstUtils.Constant(Finished)));
if (_inTryWithFinally)
{
block.Add(Expression.Assign(_gotoRouter, AstUtils.Constant(GotoRouterYielding)));
}
block.Add(Expression.Goto(_returnLabels.Peek()));
return(Expression.Block(block));
}
// Yield return
block.Add(MakeAssign(_current, value));
YieldMarker marker = GetYieldMarker(node);
block.Add(Expression.Assign(_state, AstUtils.Constant(marker.State)));
if (_inTryWithFinally)
{
block.Add(Expression.Assign(_gotoRouter, AstUtils.Constant(GotoRouterYielding)));
}
block.Add(Expression.Goto(_returnLabels.Peek()));
block.Add(Expression.Label(marker.Label));
block.Add(Expression.Assign(_gotoRouter, AstUtils.Constant(GotoRouterNone)));
block.Add(Utils.Empty());
return(Expression.Block(block));
}
