Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Speed up TopoSort by 2.7-3.3x. #3946

Merged
merged 7 commits into from
Oct 17, 2023
Merged
Show file tree
Hide file tree
Changes from 4 commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
139 changes: 96 additions & 43 deletions kernel/utils.h
Original file line number Diff line number Diff line change
Expand Up @@ -128,84 +128,137 @@ struct stackmap
// A simple class for topological sorting
// ------------------------------------------------

template<typename T, typename C = std::less<T>>
struct TopoSort
template <typename T, typename C = std::less<T>, typename OPS = hash_ops<T>> class TopoSort
{
bool analyze_loops, found_loops;
std::map<T, std::set<T, C>, C> database;
std::set<std::set<T, C>> loops;
public:
// We use this ordering of the edges in the adjacency matrix for
// exact compatibility with an older implementation.
struct IndirectCmp {
IndirectCmp(const std::vector<T> &nodes) : nodes_(nodes) {}
bool operator()(int a, int b) const
{
log_assert(static_cast<size_t>(a) < nodes_.size());
log_assert(static_cast<size_t>(b) < nodes_.size());
return node_cmp_(nodes_[a], nodes_[b]);
}
const C node_cmp_;
const std::vector<T> &nodes_;
};

bool analyze_loops;
std::map<T, int, C> node_to_index;
std::vector<std::set<int, IndirectCmp>> edges;
std::vector<T> sorted;
std::set<std::set<T, C>> loops;

TopoSort()
TopoSort() : indirect_cmp(nodes)
{
analyze_loops = true;
found_loops = false;
}

void node(T n)
int node(T n)
{
auto it = node_to_index.find(n);
if (it == node_to_index.end()) {
int index = static_cast<size_t>(nodes.size());
node_to_index[n] = index;
nodes.push_back(n);
edges.push_back(std::set<int, IndirectCmp>(indirect_cmp));
return index;
}
return it->second;
}

void edge(int l_index, int r_index) { edges[r_index].insert(l_index); }

void edge(T left, T right) { edge(node(left), node(right)); }

bool has_edges(const T &node)
{
auto it = node_to_index.find(node);
return it == node_to_index.end() || !edges[it->second].empty();
}

bool sort()
{
if (database.count(n) == 0)
database[n] = std::set<T, C>();
log_assert(GetSize(node_to_index) == GetSize(edges));
log_assert(GetSize(nodes) == GetSize(edges));

loops.clear();
sorted.clear();
found_loops = false;

std::vector<bool> marked_cells(edges.size(), false);
std::vector<bool> active_cells(edges.size(), false);
std::vector<int> active_stack;

marked_cells.reserve(edges.size());
sorted.reserve(edges.size());

for (const auto &it : node_to_index)
sort_worker(it.second, marked_cells, active_cells, active_stack);

log_assert(GetSize(sorted) == GetSize(nodes));

return !found_loops;
}

void edge(T left, T right)
// Build the more expensive representation of edges for
// a few passes that use it directly.
std::map<T, std::set<T, C>, C> get_database()
{
node(left);
database[right].insert(left);
std::map<T, std::set<T, C>, C> database;
for (size_t i = 0; i < nodes.size(); ++i) {
std::set<T, C> converted_edge_set;
for (int other_node : edges[i]) {
converted_edge_set.insert(nodes[other_node]);
}
database.emplace(nodes[i], converted_edge_set);
}
return database;
}

void sort_worker(const T &n, std::set<T, C> &marked_cells, std::set<T, C> &active_cells, std::vector<T> &active_stack)
private:
bool found_loops;
std::vector<T> nodes;
const IndirectCmp indirect_cmp;

void sort_worker(const int root_index, std::vector<bool> &marked_cells, std::vector<bool> &active_cells, std::vector<int> &active_stack)
{
if (active_cells.count(n)) {
if (active_cells[root_index]) {
found_loops = true;
if (analyze_loops) {
std::set<T, C> loop;
for (int i = GetSize(active_stack)-1; i >= 0; i--) {
loop.insert(active_stack[i]);
if (active_stack[i] == n)
for (int i = GetSize(active_stack) - 1; i >= 0; i--) {
const int index = active_stack[i];
loop.insert(nodes[index]);
if (index == root_index)
break;
}
loops.insert(loop);
}
return;
}

if (marked_cells.count(n))
if (marked_cells[root_index])
return;

if (!database.at(n).empty())
{
if (!edges[root_index].empty()) {
if (analyze_loops)
active_stack.push_back(n);
active_cells.insert(n);
active_stack.push_back(root_index);
active_cells[root_index] = true;

for (auto &left_n : database.at(n))
for (int left_n : edges[root_index])
sort_worker(left_n, marked_cells, active_cells, active_stack);

if (analyze_loops)
active_stack.pop_back();
active_cells.erase(n);
active_cells[root_index] = false;
}

marked_cells.insert(n);
sorted.push_back(n);
}

bool sort()
{
loops.clear();
sorted.clear();
found_loops = false;

std::set<T, C> marked_cells;
std::set<T, C> active_cells;
std::vector<T> active_stack;

for (auto &it : database)
sort_worker(it.first, marked_cells, active_cells, active_stack);

log_assert(GetSize(sorted) == GetSize(database));
return !found_loops;
marked_cells[root_index] = true;
sorted.push_back(nodes[root_index]);
}
};

Expand Down
2 changes: 1 addition & 1 deletion passes/cmds/glift.cc
Original file line number Diff line number Diff line change
Expand Up @@ -582,7 +582,7 @@ struct GliftPass : public Pass {
for (auto cell : module->selected_cells()) {
RTLIL::Module *tpl = design->module(cell->type);
if (tpl != nullptr) {
if (topo_modules.database.count(tpl) == 0)
if (!topo_modules.has_edges(tpl))
worklist.push_back(tpl);
topo_modules.edge(tpl, module);
non_top_modules.insert(cell->type);
Expand Down
15 changes: 10 additions & 5 deletions passes/opt/opt_expr.cc
Original file line number Diff line number Diff line change
Expand Up @@ -424,13 +424,18 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
for (auto &bit : sig)
outbit_to_cell[bit].insert(cell);
}
cells.node(cell);
}

for (auto &it_right : cell_to_inbit)
for (auto &it_sigbit : it_right.second)
for (auto &it_left : outbit_to_cell[it_sigbit])
cells.edge(it_left, it_right.first);
// Build the graph for the topological sort.
for (auto &it_right : cell_to_inbit) {
const int r_index = cells.node(it_right.first);
for (auto &it_sigbit : it_right.second) {
for (auto &it_left : outbit_to_cell[it_sigbit]) {
const int l_index = cells.node(it_left);
cells.edge(l_index, r_index);
}
}
}

cells.sort();

Expand Down
2 changes: 1 addition & 1 deletion passes/opt/share.cc
Original file line number Diff line number Diff line change
Expand Up @@ -1032,7 +1032,7 @@ struct ShareWorker
}

bool found_scc = !toposort.sort();
topo_cell_drivers = std::move(toposort.database);
topo_cell_drivers = toposort.get_database();

if (found_scc && toposort.analyze_loops)
for (auto &loop : toposort.loops) {
Expand Down
2 changes: 1 addition & 1 deletion passes/techmap/flatten.cc
Original file line number Diff line number Diff line change
Expand Up @@ -312,7 +312,7 @@ struct FlattenPass : public Pass {
for (auto cell : module->selected_cells()) {
RTLIL::Module *tpl = design->module(cell->type);
if (tpl != nullptr) {
if (topo_modules.database.count(tpl) == 0)
if (!topo_modules.has_edges(tpl))
worklist.insert(tpl);
topo_modules.edge(tpl, module);
}
Expand Down
Loading