1 files changed, 24 insertions, 9 deletions
diff --git a/common/hash_table.h b/common/hash_table.h
index 759580da..21ca8887 100644
--- a/common/hash_table.h
+++ b/common/hash_table.h
@@ -20,29 +20,44 @@
 #ifndef HASH_TABLE_H
 #define HASH_TABLE_H
 
-#if defined(NPNR_DISABLE_THREADS)
-#include <unordered_map>
-#include <unordered_set>
-#else
+#if defined(USE_ABSEIL)
 #include <absl/container/flat_hash_map.h>
 #include <absl/container/flat_hash_set.h>
+#else
+#include <unordered_map>
+#include <unordered_set>
 #endif
 
+#include <boost/functional/hash.hpp>
+
 #include "nextpnr_namespaces.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
 namespace HashTables {
-#if defined(NPNR_DISABLE_THREADS)
-template <typename Key, typename Value> using HashMap = std::unordered_map<Key, Value>;
-template <typename Value> using HashSet = std::unordered_set<Value>;
+#if defined(USE_ABSEIL)
+template <typename Key, typename Value, typename Hash = std::hash<Key>>
+using HashMap = absl::flat_hash_map<Key, Value, Hash>;
+template <typename Value, typename Hash = std::hash<Value>> using HashSet = absl::flat_hash_set<Value, Hash>;
 #else
-template <typename Key, typename Value> using HashMap = absl::flat_hash_map<Key, Value>;
-template <typename Value> using HashSet = absl::flat_hash_set<Value>;
+template <typename Key, typename Value, typename Hash = std::hash<Key>>
+using HashMap = std::unordered_map<Key, Value, Hash>;
+template <typename Value, typename Hash = std::hash<Value>> using HashSet = std::unordered_set<Value, Hash>;
 #endif
 
 }; // namespace HashTables
 
+struct PairHash
+{
+    template <typename T1, typename T2> std::size_t operator()(const std::pair<T1, T2> &idp) const noexcept
+    {
+        std::size_t seed = 0;
+        boost::hash_combine(seed, std::hash<T1>()(idp.first));
+        boost::hash_combine(seed, std::hash<T2>()(idp.second));
+        return seed;
+    }
+};
+
 NEXTPNR_NAMESPACE_END
 
 #endif /* HASH_TABLE_H */