timing: Compute domain pairs

Signed-off-by: gatecat <gatecat@ds0.me>

2 files changed, 59 insertions, 13 deletions

diff --git a/common/timing.cc b/common/timing.cc
index 4daa19b0..b34fae1e 100644
--- a/common/timing.cc
+++ b/common/timing.cc
@@ -180,7 +180,7 @@ void TimingAnalyser::setup_port_domains()
                 // registered outputs are startpoints
                 auto dom = domain_id(port.cell, fanin.other_port, fanin.edge);
                 // create per-domain data
-                pd.domains[dom].has_arrival = true;
+                pd.arrival[dom];
                 domains.at(dom).startpoints.emplace_back(port, fanin.other_port);
             }
             // copy domains across routing
@@ -214,7 +214,7 @@ void TimingAnalyser::setup_port_domains()
                 // registered inputs are startpoints
                 auto dom = domain_id(port.cell, fanout.other_port, fanout.edge);
                 // create per-domain data
-                pd.domains[dom].has_required = true;
+                pd.required[dom];
                 domains.at(dom).startpoints.emplace_back(port, fanout.other_port);
             }
             // copy port to driver
@@ -222,28 +222,45 @@ void TimingAnalyser::setup_port_domains()
                 copy_domains(port, CellPortKey(pi.net->driver), true);
         }
     }
+    // Iterate over ports and find domain paris
+    for (auto port : topological_order) {
+        auto &pd = ports.at(port);
+        for (auto &arr : pd.arrival)
+            for (auto &req : pd.required) {
+                pd.domain_pairs[domain_pair_id(arr.first, req.first)];
+            }
+    }
 }
 
-TimingAnalyser::domain_id_t TimingAnalyser::domain_id(IdString cell, IdString clock_port, ClockEdge edge)
+domain_id_t TimingAnalyser::domain_id(IdString cell, IdString clock_port, ClockEdge edge)
 {
     return domain_id(ctx->cells.at(cell)->ports.at(clock_port).net, edge);
 }
-TimingAnalyser::domain_id_t TimingAnalyser::domain_id(const NetInfo *net, ClockEdge edge)
+domain_id_t TimingAnalyser::domain_id(const NetInfo *net, ClockEdge edge)
 {
     NPNR_ASSERT(net != nullptr);
     ClockDomainKey key{net->name, edge};
-    auto inserted = domain_to_id.emplace(key, domain_to_id.size());
+    auto inserted = domain_to_id.emplace(key, domains.size());
     if (inserted.second) {
         domains.emplace_back(key);
     }
     return inserted.first->second;
 }
+domain_id_t TimingAnalyser::domain_pair_id(domain_id_t launch, domain_id_t capture)
+{
+    ClockDomainPairKey key{launch, capture};
+    auto inserted = pair_to_id.emplace(key, domain_pairs.size());
+    if (inserted.second) {
+        domain_pairs.emplace_back(key);
+    }
+    return inserted.first->second;
+}
+
 void TimingAnalyser::copy_domains(const CellPortKey &from, const CellPortKey &to, bool backward)
 {
     auto &f = ports.at(from), &t = ports.at(to);
-    for (auto &dom : f.domains)
-        if (backward ? dom.second.has_required : dom.second.has_arrival)
-            (backward ? t.domains[dom.first].has_required : t.domains[dom.first].has_arrival) = true;
+    for (auto &dom : (backward ? f.required : f.arrival))
+        (backward ? t.required : t.arrival)[dom.first];
 }
 
 CellInfo *TimingAnalyser::cell_info(const CellPortKey &key) { return ctx->cells.at(key.cell).get(); }
diff --git a/common/timing.h b/common/timing.h
index 9aa15e59..9540b6f6 100644
--- a/common/timing.h
+++ b/common/timing.h
@@ -100,6 +100,27 @@ struct ClockDomainKey
     inline bool operator==(const ClockDomainKey &other) const { return (clock == other.clock) && (edge == other.edge); }
 };
 
+typedef int domain_id_t;
+
+struct ClockDomainPairKey
+{
+    domain_id_t launch, capture;
+    ClockDomainPairKey(domain_id_t launch, domain_id_t capture) : launch(launch), capture(capture){};
+    inline bool operator==(const ClockDomainPairKey &other) const
+    {
+        return (launch == other.launch) && (capture == other.capture);
+    }
+    struct Hash
+    {
+        std::size_t operator()(const ClockDomainPairKey &arg) const noexcept
+        {
+            std::size_t seed = std::hash<domain_id_t>()(arg.launch);
+            seed ^= std::hash<domain_id_t>()(arg.capture) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
+            return seed;
+        }
+    };
+};
+
 struct TimingAnalyser
 {
   public:
@@ -113,7 +134,6 @@ struct TimingAnalyser
     void setup_port_domains();
     // To avoid storing the domain tag structure (which could get large when considering more complex constrained tag
     // cases), assign each domain an ID and use that instead
-    typedef int domain_id_t;
     // An arrival or required time entry. Stores both the min/max delays; and the traversal to reach them for critical
     // path reporting
     struct ArrivReqTime
@@ -123,10 +143,8 @@ struct TimingAnalyser
         int path_length;
     };
     // Data per port-domain tuple
-    struct PortDomainData
+    struct PortDomainPairData
     {
-        bool has_arrival = false, has_required = false;
-        ArrivReqTime arrival, required;
         delay_t setup_slack = std::numeric_limits<delay_t>::max(), hold_slack = std::numeric_limits<delay_t>::max();
         delay_t budget = std::numeric_limits<delay_t>::max();
         int max_path_length = 0;
@@ -163,7 +181,9 @@ struct TimingAnalyser
         NetPortKey net_port;
         PortType type;
         // per domain timings
-        std::unordered_map<domain_id_t, PortDomainData> domains;
+        std::unordered_map<domain_id_t, ArrivReqTime> arrival;
+        std::unordered_map<domain_id_t, ArrivReqTime> required;
+        std::unordered_map<domain_id_t, PortDomainPairData> domain_pairs;
         // cell timing arcs to (outputs)/from (inputs)  from this port
         std::vector<CellArc> cell_arcs;
         // routing delay into this port (input ports only)
@@ -178,17 +198,26 @@ struct TimingAnalyser
         std::vector<std::pair<CellPortKey, IdString>> startpoints, endpoints;
     };
 
+    struct PerDomainPair
+    {
+        PerDomainPair(ClockDomainPairKey key) : key(key){};
+        ClockDomainPairKey key;
+    };
+
     CellInfo *cell_info(const CellPortKey &key);
     PortInfo &port_info(const CellPortKey &key);
 
     domain_id_t domain_id(IdString cell, IdString clock_port, ClockEdge edge);
     domain_id_t domain_id(const NetInfo *net, ClockEdge edge);
+    domain_id_t domain_pair_id(domain_id_t launch, domain_id_t capture);
 
     void copy_domains(const CellPortKey &from, const CellPortKey &to, bool backwards);
 
     std::unordered_map<CellPortKey, PerPort, CellPortKey::Hash> ports;
     std::unordered_map<ClockDomainKey, domain_id_t, ClockDomainKey::Hash> domain_to_id;
+    std::unordered_map<ClockDomainPairKey, domain_id_t, ClockDomainPairKey::Hash> pair_to_id;
     std::vector<PerDomain> domains;
+    std::vector<PerDomainPair> domain_pairs;
 
     std::vector<CellPortKey> topological_order;