// Sort the nodes in topological order.
int CompilationGraph::TopologicalSort(std::vector<const Node*>& Out) {
std::queue<const Node*> Q;
Node* Root = getNode("root");
if (Root == 0)
return 1;
Q.push(Root);
while (!Q.empty()) {
const Node* A = Q.front();
Q.pop();
Out.push_back(A);
for (Node::const_iterator EB = A->EdgesBegin(), EE = A->EdgesEnd();
EB != EE; ++EB) {
Node* B = getNode((*EB)->ToolName());
if (B == 0)
return 1;
B->DecrInEdges();
if (B->HasNoInEdges())
Q.push(B);
}
}
return 0;
}
int CompilationGraph::CheckCycles() {
unsigned deleted = 0;
std::queue<Node*> Q;
Node* Root = getNode("root");
if (Root == 0)
return 1;
Q.push(Root);
// Try to delete all nodes that have no ingoing edges, starting from the
// root. If there are any nodes left after this operation, then we have a
// cycle. This relies on '--check-graph' not performing the topological sort.
while (!Q.empty()) {
Node* A = Q.front();
Q.pop();
++deleted;
for (Node::iterator EB = A->EdgesBegin(), EE = A->EdgesEnd();
EB != EE; ++EB) {
Node* B = getNode((*EB)->ToolName());
if (B == 0)
return 1;
B->DecrInEdges();
if (B->HasNoInEdges())
Q.push(B);
}
}
if (deleted != NodesMap.size()) {
errs() << "Error: there are cycles in the compilation graph!\n"
<< "Try inspecting the diagram produced by "
<< "'llvmc --view-graph'.\n\n";
return 1;
}
return 0;
}
