From 4e346ecfba86880c2528e3463b9beb42932d8567 Mon Sep 17 00:00:00 2001
From: gatecat <gatecat@ds0.me>
Date: Wed, 14 Apr 2021 10:14:51 +0100
Subject: Hash table refactoring

Signed-off-by: gatecat <gatecat@ds0.me>
---
 common/hash_table.h  | 33 ++++++++++++++++++++++++---------
 common/timing_opt.cc | 45 ++++-----------------------------------------
 2 files changed, 28 insertions(+), 50 deletions(-)

(limited to 'common')

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 */
diff --git a/common/timing_opt.cc b/common/timing_opt.cc
index fd2a3f83..dba96bf1 100644
--- a/common/timing_opt.cc
+++ b/common/timing_opt.cc
@@ -35,44 +35,7 @@
 #include "timing.h"
 #include "util.h"
 
-namespace std {
-
-template <> struct hash<std::pair<NEXTPNR_NAMESPACE_PREFIX IdString, NEXTPNR_NAMESPACE_PREFIX IdString>>
-{
-    std::size_t operator()(
-            const std::pair<NEXTPNR_NAMESPACE_PREFIX IdString, NEXTPNR_NAMESPACE_PREFIX IdString> &idp) const noexcept
-    {
-        std::size_t seed = 0;
-        boost::hash_combine(seed, hash<NEXTPNR_NAMESPACE_PREFIX IdString>()(idp.first));
-        boost::hash_combine(seed, hash<NEXTPNR_NAMESPACE_PREFIX IdString>()(idp.second));
-        return seed;
-    }
-};
-
-template <> struct hash<std::pair<int, NEXTPNR_NAMESPACE_PREFIX BelId>>
-{
-    std::size_t operator()(const std::pair<int, NEXTPNR_NAMESPACE_PREFIX BelId> &idp) const noexcept
-    {
-        std::size_t seed = 0;
-        boost::hash_combine(seed, hash<int>()(idp.first));
-        boost::hash_combine(seed, hash<NEXTPNR_NAMESPACE_PREFIX BelId>()(idp.second));
-        return seed;
-    }
-};
-#if !defined(ARCH_GOWIN)
-template <> struct hash<std::pair<NEXTPNR_NAMESPACE_PREFIX IdString, NEXTPNR_NAMESPACE_PREFIX BelId>>
-{
-    std::size_t
-    operator()(const std::pair<NEXTPNR_NAMESPACE_PREFIX IdString, NEXTPNR_NAMESPACE_PREFIX BelId> &idp) const noexcept
-    {
-        std::size_t seed = 0;
-        boost::hash_combine(seed, hash<NEXTPNR_NAMESPACE_PREFIX IdString>()(idp.first));
-        boost::hash_combine(seed, hash<NEXTPNR_NAMESPACE_PREFIX BelId>()(idp.second));
-        return seed;
-    }
-};
-#endif
-} // namespace std
+#include "hash_table.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
@@ -478,9 +441,9 @@ class TimingOptimiser
 
         // Actual BFS path optimisation algorithm
         std::unordered_map<IdString, std::unordered_map<BelId, delay_t>> cumul_costs;
-        std::unordered_map<std::pair<IdString, BelId>, std::pair<IdString, BelId>> backtrace;
+        std::unordered_map<std::pair<IdString, BelId>, std::pair<IdString, BelId>, PairHash> backtrace;
         std::queue<std::pair<int, BelId>> visit;
-        std::unordered_set<std::pair<int, BelId>> to_visit;
+        std::unordered_set<std::pair<int, BelId>, PairHash> to_visit;
 
         for (auto startbel : cell_neighbour_bels[path_cells.front()]) {
             // Swap for legality check
@@ -609,7 +572,7 @@ class TimingOptimiser
     std::unordered_map<IdString, std::unordered_set<BelId>> cell_neighbour_bels;
     std::unordered_map<BelId, std::unordered_set<IdString>> bel_candidate_cells;
     // Map cell ports to net delay limit
-    std::unordered_map<std::pair<IdString, IdString>, delay_t> max_net_delay;
+    std::unordered_map<std::pair<IdString, IdString>, delay_t, PairHash> max_net_delay;
     Context *ctx;
     TimingOptCfg cfg;
     TimingAnalyser tmg;
-- 
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