sigmap: take the signorm index's map directly instead of via connections()

kernel/rtlil.h

@@ -144,6 +144,8 @@ namespace RTLIL
 	struct PortBit;
 };
 
+struct SigMap;
+
 
 // TODO clean up?
 extern int64_t signorm_ns;
@@ -3077,6 +3079,8 @@ public:
 	const pool<PortBit> &fanout(SigBit bit);
 	const dict<SigBit, pool<PortBit>> &signorm_fanout() const;
 
+	const SigMap *signorm_sigmap();
+
 	// Equivalent to `connect(lhs, rhs)` followed by `sigNormalize()` for the
 	// merge implied by this single connection: updates the sigmap, promotes
 	// the driven side as canonical, and re-normalizes any existing fanout

kernel/rtlil_bufnorm.cc

@@ -278,6 +278,7 @@ struct RTLIL::SigNormIndex
 		signorm_restore_ns += time_ns;
 		++signorm_restore_count;
 	}
+
 };
 
 
@@ -422,6 +423,21 @@ const std::vector<RTLIL::SigSig> &RTLIL::Module::connections() const
 	return connections_;
 }
 
+const SigMap *RTLIL::Module::signorm_sigmap()
+{
+	if (sig_norm_index == nullptr)
+		return nullptr;
+
+	int64_t start = PerformanceTimer::query();
+	sig_norm_index->flush_connections();
+	int64_t time_ns = PerformanceTimer::query() - start;
+	Pass::subtract_from_current_runtime_ns(time_ns);
+	signorm_restore_ns += time_ns;
+	++signorm_restore_count;
+
+	return &sig_norm_index->sigmap;
+}
+
 void RTLIL::Module::new_connections(const std::vector<RTLIL::SigSig> &new_conn)
 {
 	if (sig_norm_index != nullptr) {

kernel/sigtools.h

@@ -301,6 +301,11 @@ struct SigMap final : public SigMapView
 	// Rebuild SigMap for all connections in module
 	void set(RTLIL::Module *module)
 	{
+		if (const SigMap *index_sigmap = module->signorm_sigmap()) {
+			database = index_sigmap->database;
+			return;
+		}
+
 		int bitcount = 0;
 		for (auto &it : module->connections())
 			bitcount += it.first.size();