private void EmitGeneratorTry(CodeGen cg, TryFlowResult flow)
{
//
// Initialize the flow control flag
//
Slot flowControlFlag = null;
if (flow.Any)
{
flowControlFlag = cg.GetLocalTmp(typeof(int));
cg.EmitInt(CodeGen.FinallyExitsNormally);
flowControlFlag.EmitSet(cg);
}
Slot exception = null;
if (_finally != null)
{
exception = cg.GetTemporarySlot(typeof(Exception));
cg.EmitNull();
exception.EmitSet(cg);
}
//******************************************************************
// Entering the try block
//******************************************************************
if (_target != null)
{
cg.MarkLabel(_target.EnsureLabel(cg));
}
//******************************************************************
// If we have a 'finally', transform it into try..catch..finally
// and rethrow
//******************************************************************
Label endFinallyBlock = new Label();
if (_finally != null)
{
cg.PushExceptionBlock(TargetBlockType.Try, flowControlFlag);
cg.BeginExceptionBlock();
endFinallyBlock = cg.DefineLabel();
//**************************************************************
// If there is a yield in any catch, that catch will be hoisted
// and we need to dispatch to it from here
//**************************************************************
if (_yieldInCatch)
{
EmitYieldDispatch(_catchYields, cg);
}
if (YieldInBlock(_finallyYields))
{
foreach (YieldTarget yt in _finallyYields)
{
cg.GotoRouter.EmitGet(cg);
cg.EmitInt(yt.Index);
cg.Emit(OpCodes.Beq, endFinallyBlock);
}
}
}
//******************************************************************
// If we have a 'catch', start a try block to handle all the catches
//******************************************************************
Label endCatchBlock = new Label();
if (HaveHandlers())
{
cg.PushExceptionBlock(TargetBlockType.Try, flowControlFlag);
endCatchBlock = cg.BeginExceptionBlock();
}
//******************************************************************
// Emit the try block body
//******************************************************************
// First, emit the dispatch within the try block
EmitYieldDispatch(_tryYields, cg);
// Then, emit the actual body
_body.Emit(cg);
//cg.EmitSequencePointNone();
//******************************************************************
// Emit the catch blocks
//******************************************************************
if (HaveHandlers())
{
List <CatchRecord> catches = new List <CatchRecord>();
cg.PushExceptionBlock(TargetBlockType.Catch, flowControlFlag);
foreach (CatchBlock cb in _handlers)
{
cg.BeginCatchBlock(cb.Test);
if (cb.Yield)
{
// The catch block body contains yield, therefore
// delay the body emit till after the try block.
Slot slot = cg.GetLocalTmp(cb.Test);
slot.EmitSet(cg);
catches.Add(new CatchRecord(slot, cb));
}
else
{
// Save the exception (if the catch block asked for it) or pop
EmitSaveExceptionOrPop(cg, cb);
// Emit the body right now, since it doesn't contain yield
cb.Body.Emit(cg);
}
}
cg.PopTargets(TargetBlockType.Catch);
cg.EndExceptionBlock();
cg.PopTargets(TargetBlockType.Try);
//******************************************************************
// Emit the postponed catch block bodies (with yield in them)
//******************************************************************
foreach (CatchRecord cr in catches)
{
Label next = cg.DefineLabel();
cr.Slot.EmitGet(cg);
cg.EmitNull();
cg.Emit(OpCodes.Beq, next);
if (cr.Block.Slot != null)
{
cr.Block.Slot.EmitSet(cg, cr.Slot);
}
cg.FreeLocalTmp(cr.Slot);
cr.Block.Body.Emit(cg);
cg.MarkLabel(next);
//cg.EmitSequencePointNone();
}
}
//******************************************************************
// Emit the finally body
//******************************************************************
if (_finally != null)
{
cg.MarkLabel(endFinallyBlock);
cg.PushExceptionBlock(TargetBlockType.Catch, flowControlFlag);
cg.BeginCatchBlock(typeof(Exception));
exception.EmitSet(cg);
cg.PopTargets(TargetBlockType.Catch);
cg.PushExceptionBlock(TargetBlockType.Finally, flowControlFlag);
cg.BeginFinallyBlock();
Label noExit = cg.DefineLabel();
cg.GotoRouter.EmitGet(cg);
cg.EmitInt(CodeGen.GotoRouterYielding);
cg.Emit(OpCodes.Bne_Un_S, noExit);
cg.Emit(OpCodes.Endfinally);
cg.MarkLabel(noExit);
EmitYieldDispatch(_finallyYields, cg);
// Emit the finally body
_finally.Emit(cg);
// Rethrow the exception, if any
Label noThrow = cg.DefineLabel();
exception.EmitGet(cg);
cg.EmitNull();
cg.Emit(OpCodes.Beq, noThrow);
exception.EmitGet(cg);
cg.Emit(OpCodes.Throw);
cg.MarkLabel(noThrow);
cg.FreeLocalTmp(exception);
cg.EndExceptionBlock();
cg.PopTargets(TargetBlockType.Finally);
cg.PopTargets(TargetBlockType.Try);
//
// Emit the flow control for finally, if there was any.
//
EmitFinallyFlowControl(cg, flow, flowControlFlag);
//cg.EmitSequencePointNone();
}
// Clear the target labels
ClearLabels(_tryYields);
ClearLabels(_catchYields);
if (_target != null)
{
_target.Clear();
}
}
public Label EnsureLabel(CodeGen cg)
{
Debug.Assert(_target != null);
return(_target.EnsureLabel(cg));
}
