Merge branch 'master' into add_formatting_package

Author: amin1377

vpr/src/pack/prepack.cpp

@@ -107,13 +107,11 @@ static void init_molecule_chain_info(const AtomBlockId blk_id,
                                      const AtomNetlist& atom_nlist);
 
 static AtomBlockId get_sink_block(const AtomBlockId block_id,
-                                  const t_model_ports* model_port,
-                                  const BitIndex pin_number,
+                                  const t_pack_pattern_connections& connections,
                                   const AtomNetlist& atom_nlist);
 
 static AtomBlockId get_driving_block(const AtomBlockId block_id,
-                                     const t_model_ports* model_port,
-                                     const BitIndex pin_number,
+                                     const t_pack_pattern_connections& connections,
                                      const AtomNetlist& atom_nlist);
 
 static void print_chain_starting_points(t_pack_patterns* chain_pattern);
@@ -1047,17 +1045,13 @@ static bool try_expand_molecule(t_pack_molecule& molecule,
             // this block is the driver of this connection
             if (block_connection->from_block == pattern_block) {
                 // find the block this connection is driving and add it to the queue
-                auto port_model = block_connection->from_pin->port->model_port;
-                auto ipin = block_connection->from_pin->pin_number;
-                auto sink_blk_id = get_sink_block(block_id, port_model, ipin, atom_nlist);
+                auto sink_blk_id = get_sink_block(block_id, *block_connection, atom_nlist);
                 // add this sink block id with its corresponding pattern block to the queue
                 pattern_block_queue.push(std::make_pair(block_connection->to_block, sink_blk_id));
                 // this block is being driven by this connection
             } else if (block_connection->to_block == pattern_block) {
                 // find the block that is driving this connection and it to the queue
-                auto port_model = block_connection->to_pin->port->model_port;
-                auto ipin = block_connection->to_pin->pin_number;
-                auto driver_blk_id = get_driving_block(block_id, port_model, ipin, atom_nlist);
+                auto driver_blk_id = get_driving_block(block_id, *block_connection, atom_nlist);
                 // add this driver block id with its corresponding pattern block to the queue
                 pattern_block_queue.push(std::make_pair(block_connection->from_block, driver_blk_id));
             }
@@ -1076,62 +1070,94 @@ static bool try_expand_molecule(t_pack_molecule& molecule,
 /**
  * Find the atom block in the netlist driven by this pin of the input atom block
  * If doesn't exist return AtomBlockId::INVALID()
- * Limitation: The block should be driving only one sink block
+ *      TODO: Limitation — For pack patterns other than chains, 
+ *            the block should be driven by only one block
  *      block_id   : id of the atom block that is driving the net connected to the sink block
- *      model_port : the model of the port driving the net
- *      pin_number : the pin_number of the pin driving the net (pin index within the port)
+ *      connections : pack pattern connections from the given block
  */
 static AtomBlockId get_sink_block(const AtomBlockId block_id,
-                                  const t_model_ports* model_port,
-                                  const BitIndex pin_number,
+                                  const t_pack_pattern_connections& connections,
                                   const AtomNetlist& atom_nlist) {
-    auto port_id = atom_nlist.find_atom_port(block_id, model_port);
-
-    if (port_id) {
-        auto net_id = atom_nlist.port_net(port_id, pin_number);
-        if (net_id && atom_nlist.net_sinks(net_id).size() == 1) { /* Single fanout assumption */
-            auto net_sinks = atom_nlist.net_sinks(net_id);
-            auto sink_pin_id = *(net_sinks.begin());
-            return atom_nlist.pin_block(sink_pin_id);
-        }
+    const t_model_ports* from_port_model = connections.from_pin->port->model_port;
+    const int from_pin_number = connections.from_pin->pin_number;
+    auto from_port_id = atom_nlist.find_atom_port(block_id, from_port_model);
+
+    const t_model_ports* to_port_model = connections.to_pin->port->model_port;
+    const int to_pin_number = connections.to_pin->pin_number;
+    const auto& to_pb_type = connections.to_block->pb_type;
+
+    if (!from_port_id.is_valid()) {
+        return AtomBlockId::INVALID();
     }
 
-    return AtomBlockId::INVALID();
+    auto net_id = atom_nlist.port_net(from_port_id, from_pin_number);
+    if (!net_id.is_valid()) {
+        return AtomBlockId::INVALID();
+    }
+
+    const auto& net_sinks = atom_nlist.net_sinks(net_id);
+    // Iterate through all sink blocks and check whether any of them
+    // is compatible with the block specified in the pack pattern.
+    bool connected_to_latch = false;
+    AtomBlockId pattern_sink_block_id = AtomBlockId::INVALID();
+    for (const auto& sink_pin_id : net_sinks) {
+        auto sink_block_id = atom_nlist.pin_block(sink_pin_id);
+        if (atom_nlist.block_model(sink_block_id)->name == std::string(MODEL_LATCH)) {
+            connected_to_latch = true;
+        }
+        if (primitive_type_feasible(sink_block_id, to_pb_type)) {
+            auto to_port_id = atom_nlist.find_atom_port(sink_block_id, to_port_model);
+            auto to_pin_id = atom_nlist.find_pin(to_port_id, BitIndex(to_pin_number));
+            if (to_pin_id == sink_pin_id) {
+                pattern_sink_block_id = sink_block_id;
+            }
+        }
+    }
+    // If the number of sinks is greater than 1, and one of the connected blocks is a latch,
+    // then we drop the block to avoid a situation where only registers or unregistered output
+    // of the block can use the output pin.
+    // TODO: This is a conservative assumption, and ideally we need to do analysis of the architecture
+    // before to determine which pattern is supported by the architecture.
+    if (connected_to_latch && net_sinks.size() > 1) {
+        pattern_sink_block_id = AtomBlockId::INVALID();
+    }
+    return pattern_sink_block_id;
 }
 
 /**
  * Find the atom block in the netlist driving this pin of the input atom block
  * If doesn't exist return AtomBlockId::INVALID()
  * Limitation: This driving block should be driving only the input block
  *      block_id   : id of the atom block that is connected to a net driven by the driving block
- *      model_port : the model of the port driven by the net
- *      pin_number : the pin_number of the pin driven by the net (pin index within the port)
+ *      connections : pack pattern connections from the given block
  */
 static AtomBlockId get_driving_block(const AtomBlockId block_id,
-                                     const t_model_ports* model_port,
-                                     const BitIndex pin_number,
+                                     const t_pack_pattern_connections& connections,
                                      const AtomNetlist& atom_nlist) {
-    auto port_id = atom_nlist.find_atom_port(block_id, model_port);
-
-    if (port_id) {
-        auto net_id = atom_nlist.port_net(port_id, pin_number);
-        if (net_id && atom_nlist.net_sinks(net_id).size() == 1) { /* Single fanout assumption */
+    auto to_port_model = connections.to_pin->port->model_port;
+    auto to_pin_number = connections.to_pin->pin_number;
+    auto to_port_id = atom_nlist.find_atom_port(block_id, to_port_model);
 
-            auto driver_blk_id = atom_nlist.net_driver_block(net_id);
+    if (!to_port_id.is_valid()) {
+        return AtomBlockId::INVALID();
+    }
 
-            if (model_port->is_clock) {
-                auto driver_blk_type = atom_nlist.block_type(driver_blk_id);
+    auto net_id = atom_nlist.port_net(to_port_id, to_pin_number);
+    if (net_id && atom_nlist.net_sinks(net_id).size() == 1) { /* Single fanout assumption */
+        auto driver_blk_id = atom_nlist.net_driver_block(net_id);
 
-                // TODO: support multi-clock primitives.
-                //       If the driver block is a .input block, this assertion should not
-                //       be triggered as the sink block might have only one input pin, which
-                //       would be a clock pin in case the sink block primitive is a clock generator,
-                //       resulting in a pin_number == 0.
-                VTR_ASSERT(pin_number == 1 || (pin_number == 0 && driver_blk_type == AtomBlockType::INPAD));
-            }
+        if (to_port_model->is_clock) {
+            auto driver_blk_type = atom_nlist.block_type(driver_blk_id);
 
-            return atom_nlist.net_driver_block(net_id);
+            // TODO: support multi-clock primitives.
+            //       If the driver block is a .input block, this assertion should not
+            //       be triggered as the sink block might have only one input pin, which
+            //       would be a clock pin in case the sink block primitive is a clock generator,
+            //       resulting in a pin_number == 0.
+            VTR_ASSERT(to_pin_number == 1 || (to_pin_number == 0 && driver_blk_type == AtomBlockType::INPAD));
         }
+
+        return driver_blk_id;
     }
 
     return AtomBlockId::INVALID();