private static SymbolAtom FigureOutLocalVarName(StackEntry stackEntry, ILocalVar lvar)
{
Contract.Requires(stackEntry != null);
Contract.Requires(lvar != null);
// if lvar.Name is explicitly set --> return lvar.Name
if (lvar.Name.IsValid)
{
return(lvar.Name);
}
// if lvar.Index is less than the number of captured variables in this frame --> look up the name in the parent frame.
if (stackEntry.Lambda.Captures > lvar.Index)
{
while ((stackEntry = stackEntry.Previous) != null)
{
var localVarInParentFrame = stackEntry.DebugInfo.m_locals[lvar.Index];
if (localVarInParentFrame.Name.IsValid)
{
return(localVarInParentFrame.Name);
}
}
}
// Invalid if all previous efforts failed.
return(SymbolAtom.Invalid);
}
/// <nodoc />
internal void Link(ref StackEntry current)
{
Contract.Requires(Previous == null);
Depth = current?.Depth + 1 ?? 1;
Previous = current;
current = this;
}
/// <nodoc />
internal static StackEntry Unlink(ref StackEntry current)
{
Contract.Requires(current != null);
var freedStackEntry = current;
current = current.Previous;
freedStackEntry.Previous = null;
return(freedStackEntry);
}
/// <summary>
/// Returns a list of currently accessible local variables for a given stack entry, respecting variable shadowing inside of lambdas.
/// </summary>
public static IReadOnlyList <ILocalVar> ComputeCurrentLocals(StackEntry stackEntry)
{
var debugInfo = stackEntry?.DebugInfo;
if (debugInfo == null)
{
return(CollectionUtilities.EmptyArray <ILocalVar>());
}
return(stackEntry.DebugInfo.m_locals
.Select(arg => (ILocalVar) new ComputedLocalVar(arg.Index, FigureOutLocalVarName(stackEntry, arg), arg.Value))
.Where(p => p.Name.IsValid)
.GroupBy(p => p.Name)
.Select(grp => grp.Last())
.ToArray());
}
