internal void GenerateMoveNextAndDispose(BoundStatement body, SynthesizedImplementationMethod moveNextMethod, SynthesizedImplementationMethod disposeMethod)
{
// scan body for yielding Trys
_yieldsInTryAnalysis = new YieldsInTryAnalysis(body);
if (_yieldsInTryAnalysis.ContainsYieldsInTrys())
{
// adjust for the method Try/Fault block that we will put around the body.
_tryNestingLevel++;
}
///////////////////////////////////
// Generate the body for MoveNext()
///////////////////////////////////
F.CurrentMethod = moveNextMethod;
int initialState;
GeneratedLabelSymbol initialLabel;
AddState(out initialState, out initialLabel);
var newBody = (BoundStatement)Visit(body);
// switch(cachedState) {
// case 0: goto state_0;
// case 1: goto state_1;
// //etc
// default: return false;
// }
// state_0:
// state = -1;
// [[rewritten body]]
newBody = F.Block(ImmutableArray.Create(cachedState),
F.Block(
F.HiddenSequencePoint(),
F.Assignment(F.Local(cachedState), F.Field(F.This(), stateField))
),
Dispatch(),
GenerateReturn(finished: true),
F.Label(initialLabel),
F.Assignment(F.Field(F.This(), stateField), F.Literal(StateMachineStates.NotStartedStateMachine)),
newBody);
//
// C# spec requires that iterators trap all exceptions and self-dispose eagerly.
//
// 10.14.4.1 The MoveNext method
// . . .
// When an exception is thrown and propagated out of the iterator block:
// o Appropriate finally blocks in the iterator body will have been executed by the exception propagation.
// o The state of the enumerator object is changed to after.
// o The exception propagation continues to the caller of the MoveNext method.
// . . .
//
if (_yieldsInTryAnalysis.ContainsYieldsInTrys())
{
// try
// {
// body;
// }
// fault
// {
// this.Dispose();
// }
var faultBlock = F.Block(F.ExpressionStatement(F.Call(F.This(), disposeMethod)));
newBody = F.Fault((BoundBlock)newBody, faultBlock);
}
newBody = HandleReturn(newBody);
F.CloseMethod(F.SequencePoint(body.Syntax, newBody));
///////////////////////////////////
// Generate the body for Dispose().
///////////////////////////////////
F.CurrentMethod = disposeMethod;
var rootFrame = _currentFinallyFrame;
if (rootFrame.knownStates == null)
{
// nothing to finalize
F.CloseMethod(F.Return());
}
else
{
var stateLocal = F.SynthesizedLocal(stateField.Type);
var state = F.Local(stateLocal);
var disposeBody = F.Block(
ImmutableArray.Create<LocalSymbol>(stateLocal),
F.Assignment(F.Local(stateLocal), F.Field(F.This(), stateField)),
EmitFinallyFrame(rootFrame, state),
F.Return());
F.CloseMethod(disposeBody);
}
}
internal void GenerateMoveNextAndDispose(BoundStatement body, SynthesizedImplementationMethod moveNextMethod, SynthesizedImplementationMethod disposeMethod)
{
// scan body for yielding try blocks
_yieldsInTryAnalysis = new YieldsInTryAnalysis(body);
if (_yieldsInTryAnalysis.ContainsYieldsInTrys())
{
// adjust for the method Try/Fault block that we will put around the body.
_tryNestingLevel++;
}
///////////////////////////////////
// Generate the body for MoveNext()
///////////////////////////////////
F.CurrentFunction = moveNextMethod;
int initialState;
GeneratedLabelSymbol initialLabel;
AddState(out initialState, out initialLabel);
var newBody = (BoundStatement)Visit(body);
// switch(cachedState) {
// case 0: goto state_0;
// case 1: goto state_1;
// //etc
// default: return false;
// }
// state_0:
// state = -1;
// [optional: cachedThis = capturedThis;]
// [[rewritten body]]
newBody = F.Block((object)cachedThis == null ?
ImmutableArray.Create(cachedState) :
ImmutableArray.Create(cachedState, cachedThis),
F.HiddenSequencePoint(),
F.Assignment(F.Local(cachedState), F.Field(F.This(), stateField)),
CacheThisIfNeeded(),
Dispatch(),
GenerateReturn(finished: true),
F.Label(initialLabel),
F.Assignment(F.Field(F.This(), stateField), F.Literal(StateMachineStates.NotStartedStateMachine)),
newBody);
//
// C# spec requires that iterators trap all exceptions and self-dispose eagerly.
//
// 10.14.4.1 The MoveNext method
// . . .
// When an exception is thrown and propagated out of the iterator block:
// o Appropriate finally blocks in the iterator body will have been executed by the exception propagation.
// o The state of the enumerator object is changed to after.
// o The exception propagation continues to the caller of the MoveNext method.
// . . .
//
if (_yieldsInTryAnalysis.ContainsYieldsInTrys())
{
// try
// {
// body;
// }
// fault
// {
// this.Dispose();
// }
var faultBlock = F.Block(F.ExpressionStatement(F.Call(F.This(), disposeMethod)));
newBody = F.Fault((BoundBlock)newBody, faultBlock);
}
newBody = HandleReturn(newBody);
F.CloseMethod(F.SequencePoint(body.Syntax, newBody));
///////////////////////////////////
// Generate the body for Dispose().
///////////////////////////////////
F.CurrentFunction = disposeMethod;
var rootFrame = _currentFinallyFrame;
if (rootFrame.knownStates == null)
{
// nothing to finalize
F.CloseMethod(F.Return());
}
else
{
var stateLocal = F.SynthesizedLocal(stateField.Type.TypeSymbol);
var state = F.Local(stateLocal);
var disposeBody = F.Block(
ImmutableArray.Create <LocalSymbol>(stateLocal),
F.Assignment(F.Local(stateLocal), F.Field(F.This(), stateField)),
EmitFinallyFrame(rootFrame, state),
F.Return());
F.CloseMethod(disposeBody);
}
}
