// Returns deterministically ordered list of variables that ought to be hoisted.
public static OrderedSet <Symbol> Analyze(CSharpCompilation compilation, MethodSymbol method, BoundNode node, DiagnosticBag diagnostics)
{
var initiallyAssignedVariables = UnassignedVariablesWalker.Analyze(compilation, method, node, convertInsufficientExecutionStackExceptionToCancelledByStackGuardException: true);
var walker = new IteratorAndAsyncCaptureWalker(compilation, method, node, new NeverEmptyStructTypeCache(), initiallyAssignedVariables);
walker._convertInsufficientExecutionStackExceptionToCancelledByStackGuardException = true;
bool badRegion = false;
walker.Analyze(ref badRegion);
Debug.Assert(!badRegion);
if (!method.IsStatic && method.ContainingType.TypeKind == TypeKind.Struct)
{
// It is possible that the enclosing method only *writes* to the enclosing struct, but in that
// case it should be considered captured anyway so that we have a proxy for it to write to.
walker.CaptureVariable(method.ThisParameter, node.Syntax);
}
var variablesToHoist = walker._variablesToHoist;
var lazyDisallowedCaptures = walker._lazyDisallowedCaptures;
var allVariables = walker.variableBySlot;
walker.Free();
if (lazyDisallowedCaptures != null)
{
foreach (var kvp in lazyDisallowedCaptures)
{
var variable = kvp.Key;
var type = (variable.Kind == SymbolKind.Local) ? ((LocalSymbol)variable).Type.TypeSymbol : ((ParameterSymbol)variable).Type.TypeSymbol;
if (variable is SynthesizedLocal local && local.SynthesizedKind == SynthesizedLocalKind.Spill)
{
Debug.Assert(local.Type.IsRestrictedType());
diagnostics.Add(ErrorCode.ERR_ByRefTypeAndAwait, local.Locations[0], local.Type);
}
else
{
foreach (CSharpSyntaxNode syntax in kvp.Value)
{
// CS4013: Instance of type '{0}' cannot be used inside an anonymous function, query expression, iterator block or async method
diagnostics.Add(ErrorCode.ERR_SpecialByRefInLambda, syntax.Location, type);
}
}
}
internal static HashSet <Symbol> Analyze(CSharpCompilation compilation, Symbol member, BoundNode node,
bool convertInsufficientExecutionStackExceptionToCancelledByStackGuardException = false)
{
var walker = new UnassignedVariablesWalker(compilation, member, node);
if (convertInsufficientExecutionStackExceptionToCancelledByStackGuardException)
{
walker._convertInsufficientExecutionStackExceptionToCancelledByStackGuardException = true;
}
try
{
bool badRegion = false;
var result = walker.Analyze(ref badRegion);
return(badRegion ? new HashSet <Symbol>() : result);
}
finally
{
walker.Free();
}
}