public static bool Check(Program program)
{
var checkingContext = new CheckingContext(null);
var functionDependencyChecker = new FunctionDependencyChecker();
program.TopLevelDeclarations.OfType <Function>().Iter(function =>
{
var expr = QKeyValue.FindExprAttribute(function.Attributes, "inline");
if (expr != null && expr.Type != Type.Bool)
{
checkingContext.Error(function.tok, "Parameter to :inline attribute on a function must be Boolean");
}
if (QKeyValue.FindBoolAttribute(function.Attributes, "inline") &&
QKeyValue.FindBoolAttribute(function.Attributes, "define"))
{
checkingContext.Error(function.tok, "A function may not have both :inline and :define attributes");
}
if (QKeyValue.FindBoolAttribute(function.Attributes, "inline") &&
function.Body == null)
{
checkingContext.Error(function.tok, "Function with :inline attribute must have a body");
}
if (QKeyValue.FindBoolAttribute(function.Attributes, "define") &&
function.DefinitionBody == null)
{
checkingContext.Error(function.tok, "Function with :define attribute must have a body");
}
});
if (checkingContext.ErrorCount > 0)
{
return(false);
}
program.TopLevelDeclarations.OfType <Function>()
.Iter(function => functionDependencyChecker.VisitFunction(function));
var functionDependencyGraph = functionDependencyChecker.functionDependencyGraph;
var selfLoops = functionDependencyGraph.Edges.SelectMany(edge =>
edge.Item1 == edge.Item2 ? new[] { edge.Item1 } : Enumerable.Empty <Function>()).ToHashSet();
var sccs = new StronglyConnectedComponents <Function>(
functionDependencyGraph.Nodes,
functionDependencyGraph.Predecessors,
functionDependencyGraph.Successors);
sccs.Compute();
sccs.Iter(scc =>
{
if (scc.Count > 1 ||
scc.Count == 1 && selfLoops.Contains(scc.First()))
{
var errorMsg = "Call cycle detected among functions";
var first = true;
var token = Token.NoToken;
scc.Iter(function =>
{
if (first)
{
first = false;
errorMsg += ": ";
token = function.tok;
}
else
{
errorMsg += ", ";
}
errorMsg += function.Name;
});
checkingContext.Error(token, errorMsg);
}
});
return(checkingContext.ErrorCount == 0);
}