/// <summary>
/// Create a context to compile expressions within a method scope.
/// </summary>
internal CompilationContext(
CSharpCompilation compilation,
MethodSymbol currentFrame,
ImmutableArray<LocalSymbol> locals,
InScopeHoistedLocals inScopeHoistedLocals,
MethodDebugInfo<TypeSymbol, LocalSymbol> methodDebugInfo,
CSharpSyntaxNode syntax)
{
Debug.Assert((syntax == null) || (syntax is ExpressionSyntax) || (syntax is LocalDeclarationStatementSyntax));
// TODO: syntax.SyntaxTree should probably be added to the compilation,
// but it isn't rooted by a CompilationUnitSyntax so it doesn't work (yet).
_currentFrame = currentFrame;
_syntax = syntax;
_methodNotType = !locals.IsDefault;
// NOTE: Since this is done within CompilationContext, it will not be cached.
// CONSIDER: The values should be the same everywhere in the module, so they
// could be cached.
// (Catch: what happens in a type context without a method def?)
this.Compilation = GetCompilationWithExternAliases(compilation, methodDebugInfo.ExternAliasRecords);
// Each expression compile should use a unique compilation
// to ensure expression-specific synthesized members can be
// added (anonymous types, for instance).
Debug.Assert(this.Compilation != compilation);
this.NamespaceBinder = CreateBinderChain(
this.Compilation,
(PEModuleSymbol)currentFrame.ContainingModule,
currentFrame.ContainingNamespace,
methodDebugInfo.ImportRecordGroups);
if (_methodNotType)
{
_locals = locals;
ImmutableArray<string> displayClassVariableNamesInOrder;
GetDisplayClassVariables(
currentFrame,
_locals,
inScopeHoistedLocals,
out displayClassVariableNamesInOrder,
out _displayClassVariables,
out _hoistedParameterNames);
Debug.Assert(displayClassVariableNamesInOrder.Length == _displayClassVariables.Count);
_localsForBinding = GetLocalsForBinding(_locals, displayClassVariableNamesInOrder, _displayClassVariables);
}
else
{
_locals = ImmutableArray<LocalSymbol>.Empty;
_displayClassVariables = ImmutableDictionary<string, DisplayClassVariable>.Empty;
_localsForBinding = ImmutableArray<LocalSymbol>.Empty;
}
// Assert that the cheap check for "this" is equivalent to the expensive check for "this".
Debug.Assert(
_displayClassVariables.ContainsKey(GeneratedNames.ThisProxyFieldName()) ==
_displayClassVariables.Values.Any(v => v.Kind == DisplayClassVariableKind.This));
}
private EvaluationContext(
MethodContextReuseConstraints? methodContextReuseConstraints,
CSharpCompilation compilation,
MethodSymbol currentFrame,
ImmutableArray<LocalSymbol> locals,
InScopeHoistedLocals inScopeHoistedLocals,
MethodDebugInfo<TypeSymbol, LocalSymbol> methodDebugInfo)
{
Debug.Assert(inScopeHoistedLocals != null);
Debug.Assert(methodDebugInfo != null);
this.MethodContextReuseConstraints = methodContextReuseConstraints;
this.Compilation = compilation;
_currentFrame = currentFrame;
_locals = locals;
_inScopeHoistedLocals = inScopeHoistedLocals;
_methodDebugInfo = methodDebugInfo;
}
private static void GetDisplayClassVariables(
ArrayBuilder<string> displayClassVariableNamesInOrderBuilder,
Dictionary<string, DisplayClassVariable> displayClassVariablesBuilder,
HashSet<string> parameterNames,
InScopeHoistedLocals inScopeHoistedLocals,
DisplayClassInstanceAndFields instance,
HashSet<string> hoistedParameterNames)
{
// Display class instance. The display class fields are variables.
foreach (var member in instance.Type.GetMembers())
{
if (member.Kind != SymbolKind.Field)
{
continue;
}
var field = (FieldSymbol)member;
var fieldName = field.Name;
REPARSE:
DisplayClassVariableKind variableKind;
string variableName;
GeneratedNameKind fieldKind;
int openBracketOffset;
int closeBracketOffset;
GeneratedNames.TryParseGeneratedName(fieldName, out fieldKind, out openBracketOffset, out closeBracketOffset);
switch (fieldKind)
{
case GeneratedNameKind.AnonymousTypeField:
Debug.Assert(fieldName == field.Name); // This only happens once.
fieldName = fieldName.Substring(openBracketOffset + 1, closeBracketOffset - openBracketOffset - 1);
goto REPARSE;
case GeneratedNameKind.TransparentIdentifier:
// A transparent identifier (field) in an anonymous type synthesized for a transparent identifier.
Debug.Assert(!field.IsStatic);
continue;
case GeneratedNameKind.DisplayClassLocalOrField:
// A local that is itself a display class instance.
Debug.Assert(!field.IsStatic);
continue;
case GeneratedNameKind.HoistedLocalField:
// Filter out hoisted locals that are known to be out-of-scope at the current IL offset.
// Hoisted locals with invalid indices will be included since more information is better
// than less in error scenarios.
if (!inScopeHoistedLocals.IsInScope(fieldName))
{
continue;
}
variableName = fieldName.Substring(openBracketOffset + 1, closeBracketOffset - openBracketOffset - 1);
variableKind = DisplayClassVariableKind.Local;
Debug.Assert(!field.IsStatic);
break;
case GeneratedNameKind.ThisProxyField:
// A reference to "this".
variableName = fieldName;
variableKind = DisplayClassVariableKind.This;
Debug.Assert(!field.IsStatic);
break;
case GeneratedNameKind.None:
// A reference to a parameter or local.
variableName = fieldName;
if (parameterNames.Contains(variableName))
{
variableKind = DisplayClassVariableKind.Parameter;
hoistedParameterNames.Add(variableName);
}
else
{
variableKind = DisplayClassVariableKind.Local;
}
Debug.Assert(!field.IsStatic);
break;
default:
continue;
}
if (displayClassVariablesBuilder.ContainsKey(variableName))
{
// Only expecting duplicates for async state machine
// fields (that should be at the top-level).
Debug.Assert(displayClassVariablesBuilder[variableName].DisplayClassFields.Count() == 1);
Debug.Assert(instance.Fields.Count() >= 1); // greater depth
Debug.Assert((variableKind == DisplayClassVariableKind.Parameter) ||
(variableKind == DisplayClassVariableKind.This));
}
else if (variableKind != DisplayClassVariableKind.This || GeneratedNames.GetKind(instance.Type.ContainingType.Name) != GeneratedNameKind.LambdaDisplayClass)
{
// In async lambdas, the hoisted "this" field in the state machine type will point to the display class instance, if there is one.
// In such cases, we want to add the display class "this" to the map instead (or nothing, if it lacks one).
displayClassVariableNamesInOrderBuilder.Add(variableName);
displayClassVariablesBuilder.Add(variableName, instance.ToVariable(variableName, variableKind, field));
}
}
}
/// <summary>
/// Return a mapping of captured variables (parameters, locals, and
/// "this") to locals. The mapping is needed to expose the original
/// local identifiers (those from source) in the binder.
/// </summary>
private static void GetDisplayClassVariables(
MethodSymbol method,
ImmutableArray<LocalSymbol> locals,
InScopeHoistedLocals inScopeHoistedLocals,
out ImmutableArray<string> displayClassVariableNamesInOrder,
out ImmutableDictionary<string, DisplayClassVariable> displayClassVariables,
out ImmutableHashSet<string> hoistedParameterNames)
{
// Calculated the shortest paths from locals to instances of display
// classes. There should not be two instances of the same display
// class immediately within any particular method.
var displayClassTypes = PooledHashSet<NamedTypeSymbol>.GetInstance();
var displayClassInstances = ArrayBuilder<DisplayClassInstanceAndFields>.GetInstance();
// Add any display class instances from locals (these will contain any hoisted locals).
foreach (var local in locals)
{
var name = local.Name;
if ((name != null) && (GeneratedNames.GetKind(name) == GeneratedNameKind.DisplayClassLocalOrField))
{
var instance = new DisplayClassInstanceFromLocal((EELocalSymbol)local);
displayClassTypes.Add(instance.Type);
displayClassInstances.Add(new DisplayClassInstanceAndFields(instance));
}
}
foreach (var parameter in method.Parameters)
{
if (GeneratedNames.GetKind(parameter.Name) == GeneratedNameKind.TransparentIdentifier)
{
var instance = new DisplayClassInstanceFromParameter(parameter);
displayClassTypes.Add(instance.Type);
displayClassInstances.Add(new DisplayClassInstanceAndFields(instance));
}
}
var containingType = method.ContainingType;
bool isIteratorOrAsyncMethod = false;
if (IsDisplayClassType(containingType))
{
if (!method.IsStatic)
{
// Add "this" display class instance.
var instance = new DisplayClassInstanceFromParameter(method.ThisParameter);
displayClassTypes.Add(instance.Type);
displayClassInstances.Add(new DisplayClassInstanceAndFields(instance));
}
isIteratorOrAsyncMethod = GeneratedNames.GetKind(containingType.Name) == GeneratedNameKind.StateMachineType;
}
if (displayClassInstances.Any())
{
// Find any additional display class instances breadth first.
for (int depth = 0; GetDisplayClassInstances(displayClassTypes, displayClassInstances, depth) > 0; depth++)
{
}
// The locals are the set of all fields from the display classes.
var displayClassVariableNamesInOrderBuilder = ArrayBuilder<string>.GetInstance();
var displayClassVariablesBuilder = PooledDictionary<string, DisplayClassVariable>.GetInstance();
var parameterNames = PooledHashSet<string>.GetInstance();
if (isIteratorOrAsyncMethod)
{
Debug.Assert(IsDisplayClassType(containingType));
foreach (var field in containingType.GetMembers().OfType<FieldSymbol>())
{
// All iterator and async state machine fields (including hoisted locals) have mangled names, except
// for hoisted parameters (whose field names are always the same as the original source parameters).
var fieldName = field.Name;
if (GeneratedNames.GetKind(fieldName) == GeneratedNameKind.None)
{
parameterNames.Add(fieldName);
}
}
}
else
{
foreach (var p in method.Parameters)
{
parameterNames.Add(p.Name);
}
}
var pooledHoistedParameterNames = PooledHashSet<string>.GetInstance();
foreach (var instance in displayClassInstances)
{
GetDisplayClassVariables(
displayClassVariableNamesInOrderBuilder,
displayClassVariablesBuilder,
parameterNames,
inScopeHoistedLocals,
instance,
pooledHoistedParameterNames);
}
hoistedParameterNames = pooledHoistedParameterNames.ToImmutableHashSet<string>();
pooledHoistedParameterNames.Free();
parameterNames.Free();
displayClassVariableNamesInOrder = displayClassVariableNamesInOrderBuilder.ToImmutableAndFree();
displayClassVariables = displayClassVariablesBuilder.ToImmutableDictionary();
displayClassVariablesBuilder.Free();
}
else
{
hoistedParameterNames = ImmutableHashSet<string>.Empty;
displayClassVariableNamesInOrder = ImmutableArray<string>.Empty;
displayClassVariables = ImmutableDictionary<string, DisplayClassVariable>.Empty;
}
displayClassTypes.Free();
displayClassInstances.Free();
}
