SwitchStatement TranslateSwitch(BlockContainer switchContainer, SwitchInstruction inst)
{
Debug.Assert(switchContainer.EntryPoint.IncomingEdgeCount == 1);
var oldBreakTarget = breakTarget;
breakTarget = switchContainer; // 'break' within a switch would only leave the switch
var oldCaseLabelMapping = caseLabelMapping;
caseLabelMapping = new Dictionary <Block, ConstantResolveResult>();
TranslatedExpression value;
var strToInt = inst.Value as StringToInt;
if (strToInt != null)
{
value = exprBuilder.Translate(strToInt.Argument);
}
else
{
value = exprBuilder.Translate(inst.Value);
}
// Pick the section with the most labels as default section.
IL.SwitchSection defaultSection = inst.Sections.First();
foreach (var section in inst.Sections)
{
if (section.Labels.Count() > defaultSection.Labels.Count())
{
defaultSection = section;
}
}
var stmt = new SwitchStatement()
{
Expression = value
};
Dictionary <IL.SwitchSection, Syntax.SwitchSection> translationDictionary = new Dictionary <IL.SwitchSection, Syntax.SwitchSection>();
// initialize C# switch sections.
foreach (var section in inst.Sections)
{
// This is used in the block-label mapping.
ConstantResolveResult firstValueResolveResult;
var astSection = new Syntax.SwitchSection();
// Create case labels:
if (section == defaultSection)
{
astSection.CaseLabels.Add(new CaseLabel());
firstValueResolveResult = null;
}
else
{
var values = section.Labels.Values.Select(i => CreateTypedCaseLabel(i, value.Type, strToInt?.Map)).ToArray();
if (section.HasNullLabel)
{
astSection.CaseLabels.Add(new CaseLabel(new NullReferenceExpression()));
firstValueResolveResult = new ConstantResolveResult(SpecialType.NullType, null);
}
else
{
Debug.Assert(values.Length > 0);
firstValueResolveResult = values[0];
}
astSection.CaseLabels.AddRange(values.Select(label => new CaseLabel(exprBuilder.ConvertConstantValue(label, allowImplicitConversion: true))));
}
switch (section.Body)
{
case Branch br:
// we can only inline the block, if all branches are in the switchContainer.
if (br.TargetBlock.Parent == switchContainer && switchContainer.Descendants.OfType <Branch>().Where(b => b.TargetBlock == br.TargetBlock).All(b => BlockContainer.FindClosestSwitchContainer(b) == switchContainer))
{
caseLabelMapping.Add(br.TargetBlock, firstValueResolveResult);
}
break;
default:
break;
}
translationDictionary.Add(section, astSection);
stmt.SwitchSections.Add(astSection);
}
foreach (var section in inst.Sections)
{
var astSection = translationDictionary[section];
switch (section.Body)
{
case Branch br:
// we can only inline the block, if all branches are in the switchContainer.
if (br.TargetBlock.Parent == switchContainer && switchContainer.Descendants.OfType <Branch>().Where(b => b.TargetBlock == br.TargetBlock).All(b => BlockContainer.FindClosestSwitchContainer(b) == switchContainer))
{
ConvertSwitchSectionBody(astSection, br.TargetBlock);
}
else
{
ConvertSwitchSectionBody(astSection, section.Body);
}
break;
case Leave leave:
if (astSection.CaseLabels.Count == 1 && astSection.CaseLabels.First().Expression.IsNull&& leave.TargetContainer == switchContainer)
{
stmt.SwitchSections.Remove(astSection);
break;
}
goto default;
default:
ConvertSwitchSectionBody(astSection, section.Body);
break;
}
}
if (switchContainer != null)
{
// Translate any remaining blocks:
var lastSectionStatements = stmt.SwitchSections.Last().Statements;
foreach (var block in switchContainer.Blocks.Skip(1))
{
if (caseLabelMapping.ContainsKey(block))
{
continue;
}
lastSectionStatements.Add(new LabelStatement {
Label = block.Label
});
foreach (var nestedInst in block.Instructions)
{
var nestedStmt = Convert(nestedInst);
if (nestedStmt is BlockStatement b)
{
foreach (var nested in b.Statements)
{
lastSectionStatements.Add(nested.Detach());
}
}
else
{
lastSectionStatements.Add(nestedStmt);
}
}
Debug.Assert(block.FinalInstruction.OpCode == OpCode.Nop);
}
if (endContainerLabels.TryGetValue(switchContainer, out string label))
{
lastSectionStatements.Add(new LabelStatement {
Label = label
});
lastSectionStatements.Add(new BreakStatement());
}
}
breakTarget = oldBreakTarget;
caseLabelMapping = oldCaseLabelMapping;
return(stmt);
}