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[Tool] Bug fix in repacker for considering design constraints

This commit is contained in:
tangxifan 2021-01-17 12:26:14 -07:00
parent ea9d6bfe91
commit 8c311b8282
1 changed files with 61 additions and 20 deletions
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81
openfpga/src/repack/repack.cpp
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@ -240,9 +240,9 @@ std::vector<t_pb_graph_pin*> find_routed_pb_graph_pins_atom_net(const t_pb* pb,
* Note: this is ONLY applicable to the pb_pin of top-level pb_graph_node
***************************************************************************************/
static
int find_pb_route_remapped_source_pb_pin(const t_pb* pb,
const t_pb_graph_pin* source_pb_pin,
const AtomNetId& atom_net_id) {
std::vector<int> find_pb_route_remapped_source_pb_pin(const t_pb* pb,
const t_pb_graph_pin* source_pb_pin,
const AtomNetId& atom_net_id) {
VTR_ASSERT(true == source_pb_pin->parent_node->is_root());
std::vector<int> pb_route_indices;
@ -268,9 +268,7 @@ int find_pb_route_remapped_source_pb_pin(const t_pb* pb,
}
}
VTR_ASSERT(1 == pb_route_indices.size());
return pb_route_indices[0];
return pb_route_indices;
}
/***************************************************************************************
@ -424,44 +422,87 @@ void add_lb_router_nets(LbRouter& lb_router,
break;
}
}
/* Find the constrained net mapped to this pin in clustering results */
AtomNetId constrained_atom_net_id = AtomNetId::INVALID();
/* If the pin is constrained, we need to
* - if this is an open net, for invalid net then
* - if this is valid net name, find the net id from atom_netlist and overwrite the atom net id to mapped
* - if this is valid net name, find the net id from atom_netlist
* and overwrite the atom net id to mapped
*/
if (!constrained_net_name.empty()) {
if (std::string(REPACK_DESIGN_CONSTRAINT_OPEN_NET) == constrained_net_name) {
atom_net_id == AtomNetId::INVALID();
} else {
VTR_ASSERT_SAFE(std::string(REPACK_DESIGN_CONSTRAINT_OPEN_NET) != constrained_net_name);
atom_net_id = atom_ctx.nlist.find_net(constrained_net_name);
if (std::string(REPACK_DESIGN_CONSTRAINT_OPEN_NET) != constrained_net_name) {
constrained_atom_net_id = atom_ctx.nlist.find_net(constrained_net_name);
if (false == atom_ctx.nlist.valid_net_id(constrained_atom_net_id)) {
VTR_LOG_WARN("Invalid net '%s' to be constrained! Will drop the constraint in repacking\n",
constrained_net_name.c_str());
}
}
} else {
VTR_ASSERT_SAFE(constrained_net_name.empty());
constrained_atom_net_id = atom_net_id;
}
/* Bypass unmapped pins */
if (AtomNetId::INVALID() == atom_net_id) {
/* Bypass unmapped pins. There are 4 conditions to consider
* +======+=================+=============+================================+
* | Case | Packing results | Constraints | Decision to route |
* +======+=================+=============+================================+
* | 0 | Unmapped | Unmapped | No routing needed |
* +======+=================+=============+================================+
* | 1 | Unmapped | Mapped | Find the pb source pin that |
* | | | | drives the constrained net and |
* | | | | use it to find sink nodes |
* +======+=================+=============+================================+
* | 2 | Mapped | Unmapped | No routing needed |
* +======+=================+=============+================================+
* | 3 | Mapped | Mapped | Route with the constrained net |
* | | | | but use the packing net id to |
* | | | | find the sink nodes to route |
* +======+=================+=============+================================+
*/
if (AtomNetId::INVALID() == constrained_atom_net_id) {
continue;
}
/* If we have a net to route, it must be the constrained net */
AtomNetId atom_net_id_to_route = constrained_atom_net_id;
/* The outputs of pb_graph_node is INTERMEDIATE node in the routing resource graph,
* they are all connected to a common source node
*/
LbRRNodeId source_lb_rr_node = lb_rr_graph.find_node(LB_INTERMEDIATE, source_pb_pin);
VTR_ASSERT(true == lb_rr_graph.valid_node_id(source_lb_rr_node));
int pb_route_index = find_pb_route_remapped_source_pb_pin(pb, source_pb_pin, atom_net_id);
/* As the pin remapping is allowed during routing, we should
* - Find the routing traces from packing results which is mapped to the net
* from the same port (as remapping is allowed for pins in the same port only)
* - Find the source pb_graph_pin that drives the routing traces during packing
* - Then we can find the sink nodes
*/
std::vector<int> pb_route_indices = find_pb_route_remapped_source_pb_pin(pb, source_pb_pin, atom_net_id_to_route);
/* It could happen that the constrained net is NOT used in this clb, we just skip it for routing
* For example, a clkB net is never mapped to any ports in the pb that is clocked by clkA net
* */
int pb_route_index;
if (0 == pb_route_indices.size()) {
continue;
} else {
VTR_ASSERT(1 == pb_route_indices.size());
pb_route_index = pb_route_indices[0];
}
t_pb_graph_pin* packing_source_pb_pin = get_pb_graph_node_pin_from_block_pin(block_id, pb_route_index);
VTR_ASSERT(nullptr != packing_source_pb_pin);
/* Find all the sink pins in the pb_route, we walk through the input pins and find the pin */
std::vector<t_pb_graph_pin*> sink_pb_graph_pins = find_routed_pb_graph_pins_atom_net(pb, source_pb_pin, packing_source_pb_pin, atom_net_id, device_annotation, pb_pin_mapped_nets, pb_graph_pin_lookup_from_index);
std::vector<t_pb_graph_pin*> sink_pb_graph_pins = find_routed_pb_graph_pins_atom_net(pb, source_pb_pin, packing_source_pb_pin, atom_net_id_to_route, device_annotation, pb_pin_mapped_nets, pb_graph_pin_lookup_from_index);
std::vector<LbRRNodeId> sink_lb_rr_nodes = find_lb_net_physical_sink_lb_rr_nodes(lb_rr_graph, sink_pb_graph_pins, device_annotation);
VTR_ASSERT(sink_lb_rr_nodes.size() == sink_pb_graph_pins.size());
/* Printf for debugging only, may be enabled if verbose is enabled
*/
/* Output verbose messages for debugging only */
VTR_LOGV(verbose,
"Pb route for Net %s:\n",
atom_ctx.nlist.net_name(atom_net_id).c_str());
atom_ctx.nlist.net_name(atom_net_id_to_route).c_str());
VTR_LOGV(verbose,
"Source node:\n\t%s -> %s\n",
source_pb_pin->to_string().c_str(),
@ -477,7 +518,7 @@ void add_lb_router_nets(LbRouter& lb_router,
add_lb_router_net_to_route(lb_router, lb_rr_graph,
std::vector<LbRRNodeId>(1, source_lb_rr_node),
sink_lb_rr_nodes,
atom_ctx, atom_net_id);
atom_ctx, atom_net_id_to_route);
net_counter++;
}