/// <summary>
/// Generate the body for <c>MoveNext()</c>.
/// </summary>
protected override void CreateMoveNext()
{
Method asyncMethod = _method.Method;
BooMethodBuilder methodBuilder = _stateMachineClass.AddVirtualMethod("MoveNext", TypeSystemServices.VoidType);
methodBuilder.Method.LexicalInfo = asyncMethod.LexicalInfo;
_moveNext = methodBuilder.Entity;
TransformLocalsIntoFields(asyncMethod);
TransformParametersIntoFieldsInitializedByConstructor(_method.Method);
_exprReturnLabel = CodeBuilder.CreateLabel(methodBuilder.Method, "exprReturn", 0);
_exitLabel = CodeBuilder.CreateLabel(methodBuilder.Method, "exitLabel", 0);
_isGenericTask = _method.ReturnType.ConstructedInfo != null;
_exprRetValue = _isGenericTask
? CodeBuilder.DeclareTempLocal(_moveNext.Method, _methodToStateMachineMapper.MapType(_asyncMethodBuilderMemberCollection.ResultType))
: null;
_cachedState = CodeBuilder.DeclareLocal(methodBuilder.Method, UniqueName("state"),
TypeSystemServices.IntType);
_seenAwait = false;
var rewrittenBody = (Block)Visit(_method.Method.Body);
if (!_seenAwait)
{
Context.Warnings.Add(CompilerWarningFactory.AsyncNoAwait(_method.Method));
}
var bodyBuilder = methodBuilder.Body;
bodyBuilder.Add(CodeBuilder.CreateAssignment(
CodeBuilder.CreateLocalReference(_cachedState),
CodeBuilder.CreateMemberReference(_state)));
CheckForTryExcept();
Block bodyBlock;
if (_labels.Count > 0)
{
var dispatch =
CodeBuilder.CreateSwitch(
this.LexicalInfo,
CodeBuilder.CreateLocalReference(_cachedState),
_labels);
CheckTryJumps((MethodInvocationExpression)((ExpressionStatement)dispatch).Expression);
bodyBlock = new Block(dispatch, rewrittenBody);
}
else
{
bodyBlock = rewrittenBody;
}
InternalLocal exceptionLocal;
bodyBuilder.Add(CodeBuilder.CreateTryExcept(
this.LexicalInfo,
bodyBlock,
new ExceptionHandler
{
Declaration = CodeBuilder.CreateDeclaration(
methodBuilder.Method,
UniqueName("exception"),
TypeSystemServices.ExceptionType,
out exceptionLocal),
Block = new Block(
CodeBuilder.CreateFieldAssignment(
this.LexicalInfo,
_state,
CodeBuilder.CreateIntegerLiteral(StateMachineStates.FinishedStateMachine)),
new ExpressionStatement(
CodeBuilder.CreateMethodInvocation(
CodeBuilder.CreateMemberReference(
CodeBuilder.CreateSelfReference(_stateMachineClass.Entity),
(IField)_asyncMethodBuilderField.Entity),
_asyncMethodBuilderMemberCollection.SetException,
CodeBuilder.CreateLocalReference(exceptionLocal))),
GenerateReturn())
}));
// ReturnLabel (for the rewritten return expressions in the user's method body)
bodyBuilder.Add(_exprReturnLabel.LabelStatement);
// this.state = finishedState
bodyBuilder.Add(CodeBuilder.CreateFieldAssignment(
this.LexicalInfo,
_state,
CodeBuilder.CreateIntegerLiteral(StateMachineStates.FinishedStateMachine)));
// builder.SetResult([RetVal])
var setResultInvocation = CodeBuilder.CreateMethodInvocation(
CodeBuilder.CreateMemberReference(
CodeBuilder.CreateSelfReference(_stateMachineClass.Entity),
(IField)_asyncMethodBuilderField.Entity),
_asyncMethodBuilderMemberCollection.SetResult);
if (_isGenericTask)
{
setResultInvocation.Arguments.Add(CodeBuilder.CreateLocalReference(_exprRetValue));
}
bodyBuilder.Add(new ExpressionStatement(setResultInvocation));
// this code is hidden behind a hidden sequence point.
bodyBuilder.Add(_exitLabel.LabelStatement);
bodyBuilder.Add(new ReturnStatement());
}
