public static bool AllPathsReturn(FunctionSymbol symbol, BoundBlockStatement body)
{
if (symbol.ReturnType == TypeSymbol.Void)
{
return(true);
}
if (!body.IsValid)
{
return(false);
}
var graph = Create(body);
foreach (var toEnd in graph.End.Incoming)
{
if (!toEnd.From.Statements.Any())
{
return(false);
}
if (toEnd.From.Statements.Last().Kind != BoundNodeKind.BoundReturnStatement)
{
return(false);
}
}
return(true);
}
public List <BasicBlock> Build(BoundBlockStatement boundBlock)
{
foreach (var statement in boundBlock.Statements)
{
switch (statement.Kind)
{
case BoundNodeKind.BoundExpressionStatement:
case BoundNodeKind.BoundVariableDeclarationStatement:
case BoundNodeKind.BoundNopStatement:
statements.Add(statement);
break;
case BoundNodeKind.BoundLabelStatement:
EndBlock();
statements.Add(statement);
break;
case BoundNodeKind.BoundConditionalGotoStatement:
case BoundNodeKind.BoundGotoStatement:
case BoundNodeKind.BoundReturnStatement:
statements.Add(statement);
EndBlock();
break;
default: throw new Exception("Unexpected kind");
}
}
EndBlock();
return(blocks);
}
protected virtual BoundStatement RewriteBlockStatement(BoundBlockStatement node)
{
var builder = (ImmutableArray <BoundStatement> .Builder?)null;
for (var i = 0; i < node.Statements.Length; i++)
{
var oldStatement = node.Statements[i];
var newStatement = RewriteStatement(oldStatement);
if (newStatement != oldStatement)
{
if (builder is null)
{
builder = ImmutableArray.CreateBuilder <BoundStatement>(node.Statements.Length);
for (var j = 0; j < i; j++)
{
builder.Add(node.Statements[j]);
}
}
}
if (!(builder is null))
{
builder.Add(newStatement);
}
}
if (builder is null)
{
return(node);
}
return(new BoundBlockStatement(builder.MoveToImmutable(), node.IsValid));
}
internal static ControlFlowGraph Create(BoundBlockStatement body)
{
var basicBuilder = new BasicBlockBuilder();
var blocks = basicBuilder.Build(body);
var graphBuilder = new GraphBuilder();
return(graphBuilder.Build(blocks));
}