private void ValidateJump(LabelScopeInfo reference)
{
// Assume we can do a ret/branch
_opCode = CanReturn ? OpCodes.Ret : OpCodes.Br;
// look for a simple jump out
for (var j = reference; j != null; j = j.Parent)
{
if (_definitions.Contains(j))
{
// found it, jump is valid!
return;
}
if (j.Kind == LabelScopeKind.Finally || j.Kind == LabelScopeKind.Filter)
{
break;
}
if (j.Kind == LabelScopeKind.Try || j.Kind == LabelScopeKind.Catch)
{
_opCode = OpCodes.Leave;
}
}
_acrossBlockJump = true;
if (_node != null && _node.Type != typeof(void))
{
throw new InvalidOperationException($"Cannot jump to non-local label '{_node.Name}' with a value. Only jumps to labels defined in outer blocks can pass values.");
}
if (_definitions.Count > 1)
{
throw new InvalidOperationException($"Cannot jump to ambiguous label '{_node?.Name}'.");
}
// We didn't find an outward jump. Look for a jump across blocks
var def = _definitions.First();
var common = GraphHelper.CommonNode(def, reference, b => b.Parent);
// Assume we can do a ret/branch
_opCode = CanReturn ? OpCodes.Ret : OpCodes.Br;
// Validate that we aren't jumping across a finally
for (var j = reference; j != common; j = j.Parent)
{
switch (j.Kind)
{
case LabelScopeKind.Finally:
throw new InvalidOperationException("Control cannot leave a finally block.");
case LabelScopeKind.Filter:
throw new InvalidOperationException("Control cannot leave a filter test.");
case LabelScopeKind.Try:
case LabelScopeKind.Catch:
_opCode = OpCodes.Leave;
break;
default:
break;
}
}
// Validate that we aren't jumping into a catch or an expression
for (var j = def; j != common; j = j.Parent)
{
if (j.CanJumpInto)
{
continue;
}
if (j.Kind == LabelScopeKind.Expression)
{
throw new InvalidOperationException("Control cannot enter an expression--only statements can be jumped into.");
}
throw new InvalidOperationException("Control cannot enter a try block.");
}
}