public List <BasicBlock> Build(BoundBlockStatement block)
{
foreach (var statement in block.Statements)
{
switch (statement.Kind)
{
case BoundNodeKind.LabelStatement:
StartBlock();
_statements.Add(statement);
break;
case BoundNodeKind.GotoStatement:
case BoundNodeKind.ConditionalGotoStatement:
case BoundNodeKind.ReturnStatement:
_statements.Add(statement);
StartBlock();
break;
case BoundNodeKind.VariableDeclaration:
case BoundNodeKind.ExpressionStatement:
_statements.Add(statement);
break;
default:
throw new Exception($"Unexpected statement: {statement.Kind}");
}
}
EndBlock();
return(_blocks.ToList());
}
protected virtual BoundStatement RewriteBlockStatement(BoundBlockStatement node)
{
ImmutableArray <BoundStatement> .Builder builder = null;
for (var i = 0; i < node.Statements.Length; i++)
{
var oldStatement = node.Statements[i];
var newStatement = RewriteStatement(oldStatement);
if (newStatement != oldStatement)
{
if (builder == null)
{
builder = ImmutableArray.CreateBuilder <BoundStatement>(node.Statements.Length);
for (var j = 0; j < i; j++)
{
builder.Add(node.Statements[j]);
}
}
}
if (builder != null)
{
builder.Add(newStatement);
}
}
if (builder == null)
{
return(node);
}
return(new BoundBlockStatement(builder.MoveToImmutable()));
}
public static ControlFlowGraph Create(BoundBlockStatement body)
{
var basicBlockBuilder = new BasicBlockBuilder();
var blocks = basicBlockBuilder.Build(body);
var graphBuilder = new GraphBuilder();
return(graphBuilder.Build(blocks));
}
private static void WriteBlockStatement(BoundBlockStatement node, IndentedTextWriter writer)
{
writer.WritePunctuation(SyntaxKind.OpenBraceToken);
writer.WriteLine();
writer.Indent++;
foreach (var s in node.Statements)
{
s.WriteTo(writer);
}
writer.Indent--;
writer.WritePunctuation(SyntaxKind.CloseBraceToken);
writer.WriteLine();
}
public static bool AllPathsReturn(BoundBlockStatement body)
{
var graph = Create(body);
foreach (var branch in graph.End.Incoming)
{
var lastStatement = branch.From.Statements.LastOrDefault();
if (lastStatement == null || lastStatement.Kind != BoundNodeKind.ReturnStatement)
{
return(false);
}
}
return(true);
}
protected virtual BoundStatement RewriteBlockStatement(BoundStatement node)
{
ImmutableArray <BoundStatement> .Builder?builder = null;
var boundStatements = node switch
{
BoundBlockStatement bbs => bbs.Statements,
BoundMemberBlockStatement bmbs => bmbs.Statements,
_ => throw new Exception($"Unexpected block statement type '{node.Kind}'."),
};
for (var i = 0; i < boundStatements.Length; i++)
{
var oldStatement = boundStatements[i];
var newStatement = RewriteStatement(oldStatement);
if (newStatement != oldStatement)
{
if (builder == null)
{
builder = ImmutableArray.CreateBuilder <BoundStatement>(boundStatements.Length);
for (var j = 0; j < i; j++)
{
builder.Add(boundStatements[j]);
}
}
}
builder?.Add(newStatement);
}
if (builder == null)
{
return(node);
}
return(new BoundBlockStatement(node.Syntax, builder.MoveToImmutable()));
}