diff options
Diffstat (limited to 'src')
-rw-r--r-- | src/expr/node_manager.cpp | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/src/expr/node_manager.cpp b/src/expr/node_manager.cpp index c9d772b26..66d597a36 100644 --- a/src/expr/node_manager.cpp +++ b/src/expr/node_manager.cpp @@ -363,7 +363,10 @@ void NodeManager::reclaimZombies() { std::vector<NodeValue*> NodeManager::TopologicalSort( const std::vector<NodeValue*>& roots) { std::vector<NodeValue*> order; + // The stack of nodes to visit. The Boolean value is false when visiting the + // node in preorder and true when visiting it in postorder. std::vector<std::pair<bool, NodeValue*> > stack; + // Nodes that have been visited in both pre- and postorder NodeValueIDSet visited; const NodeValueIDSet root_set(roots.begin(), roots.end()); @@ -382,17 +385,20 @@ std::vector<NodeValue*> NodeManager::TopologicalSort( order.push_back(current); } stack.pop_back(); - } else { + } + else if (visited.find(current) == visited.end()) + { stack.back().first = true; - Assert(visited.count(current) == 0); visited.insert(current); for (unsigned i = 0; i < current->getNumChildren(); ++i) { expr::NodeValue* child = current->getChild(i); - if (visited.find(child) == visited.end()) { - stack.push_back(std::make_pair(false, child)); - } + stack.push_back(std::make_pair(false, child)); } } + else + { + stack.pop_back(); + } } } Assert(order.size() == roots.size()); |