SetupVPR.cpp

#include <vector>
#include <list>

#include "SetupVPR.h"
#include "physical_types_util.h"
#include "vtr_assert.h"
#include "vtr_util.h"
#include "vtr_log.h"
#include "vtr_time.h"

#include "vpr_types.h"
#include "vpr_error.h"
#include "vpr_utils.h"

#include "globals.h"
#include "read_xml_arch_file.h"
#include "read_fpga_interchange_arch.h"
#include "pb_type_graph.h"
#include "pack_types.h"
#include "lb_type_rr_graph.h"
#include "echo_arch.h"
#include "read_options.h"
#include "echo_files.h"
#include "clock_modeling.h"
#include "ShowSetup.h"

static void SetupNetlistOpts(const t_options& Options, t_netlist_opts& NetlistOpts);
static void SetupAPOpts(const t_options& options,
                        t_ap_opts& apOpts);
static void SetupPackerOpts(const t_options& Options,
                            t_packer_opts* PackerOpts);
static void SetupPlacerOpts(const t_options& Options,
                            t_placer_opts* PlacerOpts);
static void SetupAnnealSched(const t_options& Options,
                             t_annealing_sched* AnnealSched);
static void SetupRouterOpts(const t_options& Options, t_router_opts* RouterOpts);
static void SetupNocOpts(const t_options& Options,
                         t_noc_opts* NocOpts);
static void SetupServerOpts(const t_options& Options,
                            t_server_opts* ServerOpts);

static void SetupRoutingArch(const t_arch& Arch, t_det_routing_arch& RoutingArch);

static void SetupTiming(const t_options& Options, const bool TimingEnabled, t_timing_inf* Timing);
static void SetupSwitches(const t_arch& Arch,
                          t_det_routing_arch& RoutingArch,
                          const std::vector<t_arch_switch_inf>& arch_switches);
static void SetupAnalysisOpts(const t_options& Options, t_analysis_opts& analysis_opts);
static void SetupPowerOpts(const t_options& Options, t_power_opts* power_opts, t_arch* Arch);

/**
 * @brief Identify which switch must be used for *track* to *IPIN* connections based on architecture file specification.
 * @param Arch Architecture file specification
 * @param wire_to_arch_ipin_switch Switch id that must be used when *track* and *IPIN* are located at the same die
 * @param wire_to_arch_ipin_switch_between_dice Switch id that must be used when *track* and *IPIN* are located at different dice.
 */
static void find_ipin_cblock_switch_index(const t_arch& Arch, int& wire_to_arch_ipin_switch, int& wire_to_arch_ipin_switch_between_dice);

// Fill the data structures used when flat_routing is enabled to speed-up routing
static void alloc_and_load_intra_cluster_resources(bool reachability_analysis);
static void set_root_pin_to_pb_pin_map(t_physical_tile_type* physical_type);
// Fill the pin_num to pb_pin map in physical_type
static void add_logical_pin_to_physical_tile(int physical_pin_offset,
                                             t_logical_block_type_ptr logical_block_ptr,
                                             t_physical_tile_type* physical_type);
static void add_primitive_pin_to_physical_tile(const std::vector<int>& pin_list,
                                               int physical_class_num,
                                               t_physical_tile_type* physical_tile);
static void add_intra_tile_switches();

/**
 * Identify the pins that can directly reach class_inf
 * @param physical_tile
 * @param logical_block
 * @param class_inf
 * @param physical_class_num
 */
static void do_reachability_analysis(t_physical_tile_type* physical_tile,
                                     t_logical_block_type* logical_block,
                                     t_class* class_inf,
                                     int physical_class_num);

/**
 * @brief Sets VPR parameters and defaults.
 *
 * Does not do any error checking as this should have been done by
 * the various input checkers
 */
void SetupVPR(const t_options* options,
              const bool timingenabled,
              const bool readArchFile,
              t_file_name_opts* fileNameOpts,
              t_arch* arch,
              t_netlist_opts* netlistOpts,
              t_packer_opts* packerOpts,
              t_placer_opts* placerOpts,
              t_ap_opts* apOpts,
              t_router_opts* routerOpts,
              t_analysis_opts* analysisOpts,
              t_noc_opts* nocOpts,
              t_server_opts* serverOpts,
              t_det_routing_arch& routingArch,
              std::vector<t_lb_type_rr_node>** packerRRGraphs,
              std::vector<t_segment_inf>& segments,
              t_timing_inf* timing,
              bool* showGraphics,
              int* graphPause,
              bool* saveGraphics,
              std::string* graphicsCommands,
              t_power_opts* powerOpts,
              t_vpr_setup* vpr_setup) {
    using argparse::Provenance;

    auto& device_ctx = g_vpr_ctx.mutable_device();

    device_ctx.arch = arch;

    if (options->CircuitName.value().empty()) {
        VPR_FATAL_ERROR(VPR_ERROR_BLIF_F,
                        "No blif file found in arguments (did you specify an architecture file?)\n");
    }

    alloc_and_load_output_file_names(options->CircuitName);

    //TODO: Move fileNameOpts setup into separate function
    fileNameOpts->CircuitName = options->CircuitName;
    fileNameOpts->ArchFile = options->ArchFile;
    fileNameOpts->CircuitFile = options->CircuitFile;
    fileNameOpts->NetFile = options->NetFile;
    fileNameOpts->FlatPlaceFile = options->FlatPlaceFile;
    fileNameOpts->PlaceFile = options->PlaceFile;
    fileNameOpts->RouteFile = options->RouteFile;
    fileNameOpts->ActFile = options->ActFile;
    fileNameOpts->PowerFile = options->PowerFile;
    fileNameOpts->CmosTechFile = options->CmosTechFile;
    fileNameOpts->out_file_prefix = options->out_file_prefix;
    fileNameOpts->read_vpr_constraints_file = options->read_vpr_constraints_file;
    fileNameOpts->write_vpr_constraints_file = options->write_vpr_constraints_file;
    fileNameOpts->write_constraints_file = options->write_constraints_file;
    fileNameOpts->read_flat_place_file = options->read_flat_place_file;
    fileNameOpts->write_flat_place_file = options->write_flat_place_file;
    fileNameOpts->write_block_usage = options->write_block_usage;

    fileNameOpts->verify_file_digests = options->verify_file_digests;

    SetupNetlistOpts(*options, *netlistOpts);
    SetupPlacerOpts(*options, placerOpts);
    SetupAnnealSched(*options, &placerOpts->anneal_sched);
    SetupRouterOpts(*options, routerOpts);
    SetupAnalysisOpts(*options, *analysisOpts);
    SetupPowerOpts(*options, powerOpts, arch);
    SetupNocOpts(*options, nocOpts);
    SetupServerOpts(*options, serverOpts);

    //save the device layout, which is required to parse the architecture file
    arch->device_layout = options->device_layout;

    if (readArchFile) {
        vtr::ScopedStartFinishTimer t("Loading Architecture Description");
        switch (options->arch_format) {
            case e_arch_format::VTR:
                XmlReadArch(options->ArchFile.value().c_str(),
                            timingenabled,
                            arch,
                            device_ctx.physical_tile_types,
                            device_ctx.logical_block_types);
                break;
            case e_arch_format::FPGAInterchange:
                VTR_LOG("Use FPGA Interchange device\n");
                FPGAInterchangeReadArch(options->ArchFile.value().c_str(),
                                        timingenabled,
                                        arch,
                                        device_ctx.physical_tile_types,
                                        device_ctx.logical_block_types);
                break;
            default:
                VPR_FATAL_ERROR(VPR_ERROR_ARCH, "Invalid architecture format!");
        }
    }
    VTR_LOG("\n");

    device_ctx.EMPTY_PHYSICAL_TILE_TYPE = nullptr;
    int num_inputs = 0;
    int num_outputs = 0;
    for (auto& type : device_ctx.physical_tile_types) {
        if (type.is_empty()) {
            VTR_ASSERT(device_ctx.EMPTY_PHYSICAL_TILE_TYPE == nullptr);
            VTR_ASSERT(type.num_pins == 0);
            device_ctx.EMPTY_PHYSICAL_TILE_TYPE = &type;
        }

        if (type.is_input_type) {
            num_inputs += 1;
        }

        if (type.is_output_type) {
            num_outputs += 1;
        }
    }

    device_ctx.EMPTY_LOGICAL_BLOCK_TYPE = nullptr;
    int max_equivalent_tiles = 0;
    for (const auto& type : device_ctx.logical_block_types) {
        if (type.is_empty()) {
            VTR_ASSERT(device_ctx.EMPTY_LOGICAL_BLOCK_TYPE == nullptr);
            VTR_ASSERT(type.pb_type == nullptr);
            device_ctx.EMPTY_LOGICAL_BLOCK_TYPE = &type;
        }

        max_equivalent_tiles = std::max(max_equivalent_tiles, (int)type.equivalent_tiles.size());
    }

    VTR_ASSERT(max_equivalent_tiles > 0);
    device_ctx.has_multiple_equivalent_tiles = max_equivalent_tiles > 1;

    VTR_ASSERT(device_ctx.EMPTY_PHYSICAL_TILE_TYPE != nullptr);
    VTR_ASSERT(device_ctx.EMPTY_LOGICAL_BLOCK_TYPE != nullptr);

    if (num_inputs == 0) {
        VPR_ERROR(VPR_ERROR_ARCH,
                  "Architecture contains no top-level block type containing '.input' models");
    }

    if (num_outputs == 0) {
        VPR_ERROR(VPR_ERROR_ARCH,
                  "Architecture contains no top-level block type containing '.output' models");
    }

    segments = arch->Segments;

    SetupSwitches(*arch, routingArch, arch->switches);
    SetupRoutingArch(*arch, routingArch);
    SetupTiming(*options, timingenabled, timing);
    SetupPackerOpts(*options, packerOpts);
    SetupAPOpts(*options, *apOpts);
    routingArch.write_rr_graph_filename = options->write_rr_graph_file;
    routingArch.read_rr_graph_filename = options->read_rr_graph_file;
    routingArch.read_rr_edge_override_filename = options->read_rr_edge_override_file;

    for (auto has_global_routing : arch->layer_global_routing) {
        device_ctx.inter_cluster_prog_routing_resources.emplace_back(has_global_routing);
    }

    //Setup the default flow, if no specific stages specified
    //do all
    if (!options->do_packing
        && !options->do_legalize
        && !options->do_placement
        && !options->do_analytical_placement
        && !options->do_routing
        && !options->do_analysis) {
        //run all stages if none specified
        packerOpts->doPacking = STAGE_DO;
        placerOpts->doPlacement = STAGE_DO;
        apOpts->doAP = STAGE_SKIP; // AP not default.
        routerOpts->doRouting = STAGE_DO;
        analysisOpts->doAnalysis = STAGE_AUTO; //Deferred until implementation status known
    } else {
        //We run all stages up to the specified stage
        //Note that by checking in reverse order (i.e. analysis to packing)
        //we ensure that earlier stages override the default 'LOAD' action
        //set by later stages

        if (options->do_analysis) {
            packerOpts->doPacking = STAGE_LOAD;
            placerOpts->doPlacement = STAGE_LOAD;
            routerOpts->doRouting = STAGE_LOAD;
            analysisOpts->doAnalysis = STAGE_DO;
        }

        if (options->do_routing) {
            packerOpts->doPacking = STAGE_LOAD;
            placerOpts->doPlacement = STAGE_LOAD;
            routerOpts->doRouting = STAGE_DO;
            analysisOpts->doAnalysis = ((options->do_analysis) ? STAGE_DO : STAGE_AUTO); //Always run analysis after routing
        }

        if (options->do_placement) {
            packerOpts->doPacking = STAGE_LOAD;
            placerOpts->doPlacement = STAGE_DO;
        }

        if (options->do_analytical_placement) {
            // In the Analytical Placement flow, packing and placement are
            // integrated. Thus, these stages are skipped.
            packerOpts->doPacking = STAGE_SKIP;
            placerOpts->doPlacement = STAGE_SKIP;
            apOpts->doAP = STAGE_DO;
        }

        if (options->do_packing) {
            packerOpts->doPacking = STAGE_DO;
        }

        if (options->do_legalize) {
            packerOpts->doPacking = STAGE_LOAD;
            packerOpts->load_flat_placement = true;
        }
    }

    ShowSetup(*vpr_setup);

    /* init global variables */
    vtr::out_file_prefix = options->out_file_prefix;

    {
        vtr::ScopedStartFinishTimer t("Building complex block graph");
        alloc_and_load_all_pb_graphs(powerOpts->do_power, routerOpts->flat_routing);
        *packerRRGraphs = alloc_and_load_all_lb_type_rr_graph();
    }

    if (routerOpts->flat_routing) {
        vtr::ScopedStartFinishTimer timer("Allocate intra-cluster resources");
        // The following two functions should be called when the data structured related to t_pb_graph_node, t_pb_type,
        // and t_pb_graph_edge are initialized
        alloc_and_load_intra_cluster_resources(routerOpts->has_choke_point);
        add_intra_tile_switches();
    }

    if ((options->clock_modeling == ROUTED_CLOCK) || (options->clock_modeling == DEDICATED_NETWORK)) {
        ClockModeling::treat_clock_pins_as_non_globals();
    }

    if (getEchoEnabled() && isEchoFileEnabled(E_ECHO_LB_TYPE_RR_GRAPH)) {
        echo_lb_type_rr_graphs(getEchoFileName(E_ECHO_LB_TYPE_RR_GRAPH), *packerRRGraphs);
    }

    if (getEchoEnabled() && isEchoFileEnabled(E_ECHO_PB_GRAPH)) {
        echo_pb_graph(getEchoFileName(E_ECHO_PB_GRAPH));
    }

    *graphPause = options->GraphPause;

    *showGraphics = options->show_graphics;

    *saveGraphics = options->save_graphics;
    *graphicsCommands = options->graphics_commands;

    if (getEchoEnabled() && isEchoFileEnabled(E_ECHO_ARCH)) {
        EchoArch(getEchoFileName(E_ECHO_ARCH), device_ctx.physical_tile_types, device_ctx.logical_block_types, arch);
    }
}

static void SetupTiming(const t_options& Options, const bool TimingEnabled, t_timing_inf* Timing) {
    /* Don't do anything if they don't want timing */
    if (!TimingEnabled) {
        Timing->timing_analysis_enabled = false;
        return;
    }

    Timing->timing_analysis_enabled = TimingEnabled;
    Timing->SDCFile = Options.SDCFile;
}

/**
 * @brief This loads up VPR's arch_switch_inf data by combining the switches
 *        from the arch file with the special switches that VPR needs.
 */
static void SetupSwitches(const t_arch& Arch,
                          t_det_routing_arch& RoutingArch,
                          const std::vector<t_arch_switch_inf>& arch_switches) {
    auto& device_ctx = g_vpr_ctx.mutable_device();

    int switches_to_copy = (int)arch_switches.size();
    int num_arch_switches = (int)arch_switches.size();

    find_ipin_cblock_switch_index(Arch, RoutingArch.wire_to_arch_ipin_switch, RoutingArch.wire_to_arch_ipin_switch_between_dice);

    /* Depends on device_ctx.num_arch_switches */
    RoutingArch.delayless_switch = num_arch_switches++;

    /* Alloc the list now that we know the final num_arch_switches value */
    device_ctx.arch_switch_inf.resize(num_arch_switches);
    for (int iswitch = 0; iswitch < switches_to_copy; iswitch++) {
        device_ctx.arch_switch_inf[iswitch] = arch_switches[iswitch];
        // TODO: AM: Since I am not sure whether replacing arch_switch_in with all_sw_inf, which contains the
        //  information about intra-tile switched, would not break anything, for the time being, I decided to not remove it
        device_ctx.all_sw_inf[iswitch] = arch_switches[iswitch];
    }

    /* Delayless switch for connecting sinks and sources with their pins. */
    device_ctx.arch_switch_inf[RoutingArch.delayless_switch].set_type(SwitchType::MUX);
    device_ctx.arch_switch_inf[RoutingArch.delayless_switch].name = std::string(VPR_DELAYLESS_SWITCH_NAME);
    device_ctx.arch_switch_inf[RoutingArch.delayless_switch].R = 0.;
    device_ctx.arch_switch_inf[RoutingArch.delayless_switch].Cin = 0.;
    device_ctx.arch_switch_inf[RoutingArch.delayless_switch].Cout = 0.;
    device_ctx.arch_switch_inf[RoutingArch.delayless_switch].set_Tdel(t_arch_switch_inf::UNDEFINED_FANIN, 0.);
    device_ctx.arch_switch_inf[RoutingArch.delayless_switch].power_buffer_type = POWER_BUFFER_TYPE_NONE;
    device_ctx.arch_switch_inf[RoutingArch.delayless_switch].mux_trans_size = 0.;
    device_ctx.arch_switch_inf[RoutingArch.delayless_switch].buf_size_type = BufferSize::ABSOLUTE;
    device_ctx.arch_switch_inf[RoutingArch.delayless_switch].buf_size = 0.;
    VTR_ASSERT_MSG(device_ctx.arch_switch_inf[RoutingArch.delayless_switch].buffered(), "Delayless switch expected to be buffered (isolating)");
    VTR_ASSERT_MSG(device_ctx.arch_switch_inf[RoutingArch.delayless_switch].configurable(), "Delayless switch expected to be configurable");

    device_ctx.all_sw_inf[RoutingArch.delayless_switch] = device_ctx.arch_switch_inf[RoutingArch.delayless_switch];

    RoutingArch.global_route_switch = RoutingArch.delayless_switch;

    device_ctx.delayless_switch_idx = RoutingArch.delayless_switch;

    //Warn about non-zero Cout values for the ipin switch, since these values have no effect.
    //VPR do not model the R/C's of block internal routing connection.
    //
    //Note that we don't warn about the R value as it may be used to size the buffer (if buf_size_type is AUTO)
    if (device_ctx.arch_switch_inf[RoutingArch.wire_to_arch_ipin_switch].Cout != 0.) {
        VTR_LOG_WARN("Non-zero switch output capacitance (%g) has no effect when switch '%s' is used for connection block inputs\n",
                     device_ctx.arch_switch_inf[RoutingArch.wire_to_arch_ipin_switch].Cout, Arch.ipin_cblock_switch_name[0].c_str());
    }
}

/**
 * @brief Sets up routing structures.
 *
 * Since checks are already done, this just copies values across
 */
static void SetupRoutingArch(const t_arch& Arch,
                             t_det_routing_arch& RoutingArch) {
    RoutingArch.switch_block_type = Arch.SBType;
    RoutingArch.R_minW_nmos = Arch.R_minW_nmos;
    RoutingArch.R_minW_pmos = Arch.R_minW_pmos;
    RoutingArch.Fs = Arch.Fs;
    RoutingArch.directionality = BI_DIRECTIONAL;
    if (!Arch.Segments.empty()) {
        RoutingArch.directionality = Arch.Segments[0].directionality;
    }

    /* copy over the switch block information */
    RoutingArch.switchblocks = Arch.switchblocks;
}

static void SetupRouterOpts(const t_options& Options, t_router_opts* RouterOpts) {
    RouterOpts->do_check_rr_graph = Options.check_rr_graph;
    RouterOpts->astar_fac = Options.astar_fac;
    RouterOpts->astar_offset = Options.astar_offset;
    RouterOpts->router_profiler_astar_fac = Options.router_profiler_astar_fac;
    RouterOpts->enable_parallel_connection_router = Options.enable_parallel_connection_router;
    RouterOpts->post_target_prune_fac = Options.post_target_prune_fac;
    RouterOpts->post_target_prune_offset = Options.post_target_prune_offset;
    RouterOpts->multi_queue_num_threads = Options.multi_queue_num_threads;
    RouterOpts->multi_queue_num_queues = Options.multi_queue_num_queues;
    RouterOpts->multi_queue_direct_draining = Options.multi_queue_direct_draining;
    RouterOpts->bb_factor = Options.bb_factor;
    RouterOpts->criticality_exp = Options.criticality_exp;
    RouterOpts->max_criticality = Options.max_criticality;
    RouterOpts->max_router_iterations = Options.max_router_iterations;
    RouterOpts->init_wirelength_abort_threshold = Options.router_init_wirelength_abort_threshold;
    RouterOpts->min_incremental_reroute_fanout = Options.min_incremental_reroute_fanout;
    RouterOpts->incr_reroute_delay_ripup = Options.incr_reroute_delay_ripup;
    RouterOpts->pres_fac_mult = Options.pres_fac_mult;
    RouterOpts->max_pres_fac = Options.max_pres_fac;
    RouterOpts->route_type = Options.RouteType;
    RouterOpts->route_verbosity = Options.route_verbosity;

    RouterOpts->full_stats = Options.full_stats;

    //TODO document these?
    RouterOpts->congestion_analysis = Options.full_stats;
    RouterOpts->fanout_analysis = Options.full_stats;
    RouterOpts->switch_usage_analysis = Options.full_stats;

    RouterOpts->verify_binary_search = Options.verify_binary_search;
    RouterOpts->router_algorithm = Options.RouterAlgorithm;
    RouterOpts->fixed_channel_width = Options.RouteChanWidth;
    RouterOpts->min_channel_width_hint = Options.min_route_chan_width_hint;
    RouterOpts->read_rr_edge_metadata = Options.read_rr_edge_metadata;
    RouterOpts->reorder_rr_graph_nodes_algorithm = Options.reorder_rr_graph_nodes_algorithm;
    RouterOpts->reorder_rr_graph_nodes_threshold = Options.reorder_rr_graph_nodes_threshold;
    RouterOpts->reorder_rr_graph_nodes_seed = Options.reorder_rr_graph_nodes_seed;

    RouterOpts->initial_pres_fac = Options.initial_pres_fac;
    RouterOpts->base_cost_type = Options.base_cost_type;
    RouterOpts->first_iter_pres_fac = Options.first_iter_pres_fac;
    RouterOpts->acc_fac = Options.acc_fac;
    RouterOpts->bend_cost = Options.bend_cost;
    if (Options.do_routing) {
        RouterOpts->doRouting = STAGE_DO;
    }
    RouterOpts->routing_failure_predictor = Options.routing_failure_predictor;
    RouterOpts->routing_budgets_algorithm = Options.routing_budgets_algorithm;
    RouterOpts->save_routing_per_iteration = Options.save_routing_per_iteration;
    RouterOpts->congested_routing_iteration_threshold_frac = Options.congested_routing_iteration_threshold_frac;
    RouterOpts->route_bb_update = Options.route_bb_update;
    RouterOpts->clock_modeling = Options.clock_modeling;
    RouterOpts->two_stage_clock_routing = Options.two_stage_clock_routing;
    RouterOpts->high_fanout_threshold = Options.router_high_fanout_threshold;
    RouterOpts->high_fanout_max_slope = Options.router_high_fanout_max_slope;
    RouterOpts->router_debug_net = Options.router_debug_net;
    RouterOpts->router_debug_sink_rr = Options.router_debug_sink_rr;
    RouterOpts->router_debug_iteration = Options.router_debug_iteration;
    RouterOpts->lookahead_type = Options.router_lookahead_type;
    RouterOpts->max_convergence_count = Options.router_max_convergence_count;
    RouterOpts->reconvergence_cpd_threshold = Options.router_reconvergence_cpd_threshold;
    RouterOpts->initial_timing = Options.router_initial_timing;
    RouterOpts->update_lower_bound_delays = Options.router_update_lower_bound_delays;
    RouterOpts->first_iteration_timing_report_file = Options.router_first_iteration_timing_report_file;
    RouterOpts->strict_checks = Options.strict_checks;

    RouterOpts->write_router_lookahead = Options.write_router_lookahead;
    RouterOpts->read_router_lookahead = Options.read_router_lookahead;

    RouterOpts->write_intra_cluster_router_lookahead = Options.write_intra_cluster_router_lookahead;
    RouterOpts->read_intra_cluster_router_lookahead = Options.read_intra_cluster_router_lookahead;

    RouterOpts->router_heap = Options.router_heap;
    RouterOpts->exit_after_first_routing_iteration = Options.exit_after_first_routing_iteration;

    RouterOpts->check_route = Options.check_route;
    RouterOpts->timing_update_type = Options.timing_update_type;

    RouterOpts->max_logged_overused_rr_nodes = Options.max_logged_overused_rr_nodes;
    RouterOpts->generate_rr_node_overuse_report = Options.generate_rr_node_overuse_report;
    RouterOpts->flat_routing = Options.flat_routing;
    RouterOpts->has_choke_point = Options.router_opt_choke_points;
    RouterOpts->custom_3d_sb_fanin_fanout = Options.custom_3d_sb_fanin_fanout;
    RouterOpts->with_timing_analysis = Options.timing_analysis;
}

static void SetupAnnealSched(const t_options& Options,
                             t_annealing_sched* AnnealSched) {
    AnnealSched->alpha_t = Options.PlaceAlphaT;
    if (AnnealSched->alpha_t >= 1 || AnnealSched->alpha_t <= 0) {
        VPR_FATAL_ERROR(VPR_ERROR_OTHER, "alpha_t must be between 0 and 1 exclusive.\n");
    }

    AnnealSched->exit_t = Options.PlaceExitT;
    if (AnnealSched->exit_t <= 0) {
        VPR_FATAL_ERROR(VPR_ERROR_OTHER, "exit_t must be greater than 0.\n");
    }

    AnnealSched->init_t = Options.PlaceInitT;
    if (AnnealSched->init_t <= 0) {
        VPR_FATAL_ERROR(VPR_ERROR_OTHER, "init_t must be greater than 0.\n");
    }

    if (AnnealSched->init_t < AnnealSched->exit_t) {
        VPR_FATAL_ERROR(VPR_ERROR_OTHER, "init_t must be greater or equal to than exit_t.\n");
    }

    AnnealSched->inner_num = Options.PlaceInnerNum;
    if (AnnealSched->inner_num <= 0) {
        VPR_FATAL_ERROR(VPR_ERROR_OTHER, "inner_num must be greater than 0.\n");
    }

    AnnealSched->type = Options.anneal_sched_type;
}

/**
 * @brief Sets up the t_ap_opts structure based on users inputs and
 *        on the architecture specified.
 *
 * Error checking, such as checking for conflicting params is assumed
 * to be done beforehand
 */
void SetupAPOpts(const t_options& options,
                 t_ap_opts& apOpts) {
    apOpts.analytical_solver_type = options.ap_analytical_solver.value();
    apOpts.partial_legalizer_type = options.ap_partial_legalizer.value();
    apOpts.full_legalizer_type = options.ap_full_legalizer.value();
    apOpts.detailed_placer_type = options.ap_detailed_placer.value();
    apOpts.ap_timing_tradeoff = options.ap_timing_tradeoff.value();
    apOpts.appack_max_dist_th = options.appack_max_dist_th.value();
    apOpts.log_verbosity = options.ap_verbosity.value();
}

/**
 * @brief Sets up the t_packer_opts structure based on users inputs and
 *        on the architecture specified.
 *
 * Error checking, such as checking for conflicting params is assumed
 * to be done beforehand
 */
void SetupPackerOpts(const t_options& Options,
                     t_packer_opts* PackerOpts) {
    PackerOpts->output_file = Options.NetFile;

    PackerOpts->circuit_file_name = Options.CircuitFile;

    if (Options.do_packing) {
        PackerOpts->doPacking = STAGE_DO;
    }

    PackerOpts->allow_unrelated_clustering = Options.allow_unrelated_clustering;
    PackerOpts->connection_driven = Options.connection_driven_clustering;
    PackerOpts->timing_driven = Options.timing_driven_clustering;
    PackerOpts->cluster_seed_type = Options.cluster_seed_type;
    PackerOpts->timing_gain_weight = Options.timing_gain_weight;
    PackerOpts->connection_gain_weight = Options.connection_gain_weight;
    PackerOpts->pack_verbosity = Options.pack_verbosity;
    PackerOpts->enable_pin_feasibility_filter = Options.enable_clustering_pin_feasibility_filter;
    PackerOpts->balance_block_type_utilization = Options.balance_block_type_utilization;
    PackerOpts->target_external_pin_util = Options.target_external_pin_util;
    PackerOpts->target_device_utilization = Options.target_device_utilization;
    PackerOpts->prioritize_transitive_connectivity = Options.pack_prioritize_transitive_connectivity;
    PackerOpts->high_fanout_threshold = Options.pack_high_fanout_threshold;
    PackerOpts->transitive_fanout_threshold = Options.pack_transitive_fanout_threshold;
    PackerOpts->feasible_block_array_size = Options.pack_feasible_block_array_size;

    PackerOpts->device_layout = Options.device_layout;

    PackerOpts->timing_update_type = Options.timing_update_type;
}

static void SetupNetlistOpts(const t_options& Options, t_netlist_opts& NetlistOpts) {
    NetlistOpts.const_gen_inference = Options.const_gen_inference;
    NetlistOpts.absorb_buffer_luts = Options.absorb_buffer_luts;
    NetlistOpts.sweep_dangling_primary_ios = Options.sweep_dangling_primary_ios;
    NetlistOpts.sweep_dangling_nets = Options.sweep_dangling_nets;
    NetlistOpts.sweep_dangling_blocks = Options.sweep_dangling_blocks;
    NetlistOpts.sweep_constant_primary_outputs = Options.sweep_constant_primary_outputs;
    NetlistOpts.netlist_verbosity = Options.netlist_verbosity;
}

/**
 * @brief Sets up the s_placer_opts structure based on users input.
 *
 * Error checking, such as checking for conflicting params
 * is assumed to be done beforehand
 */
static void SetupPlacerOpts(const t_options& Options, t_placer_opts* PlacerOpts) {
    if (Options.do_placement) {
        PlacerOpts->doPlacement = STAGE_DO;
    }

    PlacerOpts->inner_loop_recompute_divider = Options.inner_loop_recompute_divider;
    PlacerOpts->quench_recompute_divider = Options.quench_recompute_divider;

    PlacerOpts->td_place_exp_first = Options.place_exp_first;

    PlacerOpts->td_place_exp_last = Options.place_exp_last;

    PlacerOpts->place_algorithm = Options.PlaceAlgorithm;
    PlacerOpts->place_quench_algorithm = Options.PlaceQuenchAlgorithm;

    PlacerOpts->constraints_file = Options.constraints_file;

    PlacerOpts->write_initial_place_file = Options.write_initial_place_file;

    PlacerOpts->read_initial_place_file = Options.read_initial_place_file;

    PlacerOpts->pad_loc_type = Options.pad_loc_type;

    PlacerOpts->place_chan_width = Options.PlaceChanWidth;

    PlacerOpts->recompute_crit_iter = Options.RecomputeCritIter;

    PlacerOpts->timing_tradeoff = Options.PlaceTimingTradeoff;

    /* Depends on PlacerOpts->place_algorithm */
    PlacerOpts->delay_offset = Options.place_delay_offset;
    PlacerOpts->delay_ramp_delta_threshold = Options.place_delay_ramp_delta_threshold;
    PlacerOpts->delay_ramp_slope = Options.place_delay_ramp_slope;
    PlacerOpts->tsu_rel_margin = Options.place_tsu_rel_margin;
    PlacerOpts->tsu_abs_margin = Options.place_tsu_abs_margin;
    PlacerOpts->delay_model_type = Options.place_delay_model;
    PlacerOpts->delay_model_reducer = Options.place_delay_model_reducer;

    PlacerOpts->place_freq = PLACE_ONCE; /* DEFAULT */

    PlacerOpts->post_place_timing_report_file = Options.post_place_timing_report_file;

    PlacerOpts->rlim_escape_fraction = Options.place_rlim_escape_fraction;
    PlacerOpts->move_stats_file = Options.place_move_stats_file;
    PlacerOpts->placement_saves_per_temperature = Options.placement_saves_per_temperature;
    PlacerOpts->place_delta_delay_matrix_calculation_method = Options.place_delta_delay_matrix_calculation_method;

    PlacerOpts->strict_checks = Options.strict_checks;

    PlacerOpts->write_placement_delay_lookup = Options.write_placement_delay_lookup;
    PlacerOpts->read_placement_delay_lookup = Options.read_placement_delay_lookup;

    PlacerOpts->allowed_tiles_for_delay_model = Options.allowed_tiles_for_delay_model;

    PlacerOpts->effort_scaling = Options.place_effort_scaling;
    PlacerOpts->timing_update_type = Options.timing_update_type;
    PlacerOpts->enable_analytic_placer = Options.enable_analytic_placer;
    PlacerOpts->place_static_move_prob = vtr::vector<e_move_type, float>(Options.place_static_move_prob.value().begin(),
                                                                         Options.place_static_move_prob.value().end());
    PlacerOpts->place_high_fanout_net = Options.place_high_fanout_net;
    PlacerOpts->place_bounding_box_mode = Options.place_bounding_box_mode;
    PlacerOpts->RL_agent_placement = Options.RL_agent_placement;
    PlacerOpts->place_agent_multistate = Options.place_agent_multistate;
    PlacerOpts->place_checkpointing = Options.place_checkpointing;
    PlacerOpts->place_agent_epsilon = Options.place_agent_epsilon;
    PlacerOpts->place_agent_gamma = Options.place_agent_gamma;
    PlacerOpts->place_dm_rlim = Options.place_dm_rlim;
    PlacerOpts->place_agent_space = Options.place_agent_space;
    PlacerOpts->place_reward_fun = Options.place_reward_fun;
    PlacerOpts->place_crit_limit = Options.place_crit_limit;
    PlacerOpts->place_agent_algorithm = Options.place_agent_algorithm;
    PlacerOpts->place_constraint_expand = Options.place_constraint_expand;
    PlacerOpts->place_constraint_subtile = Options.place_constraint_subtile;
    PlacerOpts->floorplan_num_horizontal_partitions = Options.floorplan_num_horizontal_partitions;
    PlacerOpts->floorplan_num_vertical_partitions = Options.floorplan_num_vertical_partitions;
    PlacerOpts->place_quench_only = Options.place_quench_only;

    PlacerOpts->seed = Options.Seed;

    PlacerOpts->placer_debug_block = Options.placer_debug_block;
    PlacerOpts->placer_debug_net = Options.placer_debug_net;
}

static void SetupAnalysisOpts(const t_options& Options, t_analysis_opts& analysis_opts) {
    if (Options.do_analysis) {
        analysis_opts.doAnalysis = STAGE_DO;
    }

    analysis_opts.gen_post_synthesis_netlist = Options.Generate_Post_Synthesis_Netlist;
    analysis_opts.gen_post_implementation_merged_netlist = Options.Generate_Post_Implementation_Merged_Netlist;
    analysis_opts.gen_post_implementation_sdc = Options.generate_post_implementation_sdc.value();

    analysis_opts.timing_report_npaths = Options.timing_report_npaths;
    analysis_opts.timing_report_detail = Options.timing_report_detail;
    analysis_opts.timing_report_skew = Options.timing_report_skew;
    analysis_opts.echo_dot_timing_graph_node = Options.echo_dot_timing_graph_node;

    analysis_opts.post_synth_netlist_unconn_input_handling = Options.post_synth_netlist_unconn_input_handling;
    analysis_opts.post_synth_netlist_unconn_output_handling = Options.post_synth_netlist_unconn_output_handling;
    analysis_opts.post_synth_netlist_module_parameters = Options.post_synth_netlist_module_parameters.value();

    analysis_opts.timing_update_type = Options.timing_update_type;
    analysis_opts.write_timing_summary = Options.write_timing_summary;
}

static void SetupPowerOpts(const t_options& Options, t_power_opts* power_opts, t_arch* Arch) {
    auto& device_ctx = g_vpr_ctx.mutable_device();

    power_opts->do_power = Options.do_power;

    if (power_opts->do_power) {
        if (!Arch->power)
            Arch->power = new t_power_arch();

        if (!Arch->clocks)
            Arch->clocks = new t_clock_arch();

        device_ctx.clock_arch = Arch->clocks;
    } else {
        Arch->power = nullptr;
        Arch->clocks = nullptr;
        device_ctx.clock_arch = nullptr;
    }
}

/*
 * Go through all the NoC options supplied by the user and store them internally.
 */
static void SetupNocOpts(const t_options& Options, t_noc_opts* NocOpts) {
    // assign the noc specific options from the command line
    NocOpts->noc = Options.noc;
    NocOpts->noc_flows_file = Options.noc_flows_file;
    NocOpts->noc_routing_algorithm = Options.noc_routing_algorithm;
    NocOpts->noc_placement_weighting = Options.noc_placement_weighting;
    NocOpts->noc_aggregate_bandwidth_weighting = Options.noc_agg_bandwidth_weighting;
    NocOpts->noc_latency_constraints_weighting = Options.noc_latency_constraints_weighting;
    NocOpts->noc_latency_weighting = Options.noc_latency_weighting;
    NocOpts->noc_congestion_weighting = Options.noc_congestion_weighting;
    NocOpts->noc_centroid_weight = Options.noc_centroid_weight;
    NocOpts->noc_swap_percentage = Options.noc_swap_percentage;
    NocOpts->noc_sat_routing_bandwidth_resolution = Options.noc_sat_routing_bandwidth_resolution;
    NocOpts->noc_sat_routing_latency_overrun_weighting = Options.noc_sat_routing_latency_overrun_weighting_factor;
    NocOpts->noc_sat_routing_congestion_weighting = Options.noc_sat_routing_congestion_weighting_factor;
    if (Options.noc_sat_routing_num_workers.provenance() == argparse::Provenance::SPECIFIED) {
        NocOpts->noc_sat_routing_num_workers = Options.noc_sat_routing_num_workers;
    } else {
        NocOpts->noc_sat_routing_num_workers = (int)Options.num_workers;
    }
    NocOpts->noc_sat_routing_log_search_progress = Options.noc_sat_routing_log_search_progress;
    NocOpts->noc_placement_file_name = Options.noc_placement_file_name;
}

static void SetupServerOpts(const t_options& Options, t_server_opts* ServerOpts) {
    ServerOpts->is_server_mode_enabled = Options.is_server_mode_enabled;
    ServerOpts->port_num = Options.server_port_num;
}

static void find_ipin_cblock_switch_index(const t_arch& Arch, int& wire_to_arch_ipin_switch, int& wire_to_arch_ipin_switch_between_dice) {
    for (int cb_switch_name_index = 0; cb_switch_name_index < (int)Arch.ipin_cblock_switch_name.size(); cb_switch_name_index++) {
        int ipin_cblock_switch_index = UNDEFINED;
        for (int iswitch = 0; iswitch < (int)Arch.switches.size(); ++iswitch) {
            if (Arch.switches[iswitch].name == Arch.ipin_cblock_switch_name[cb_switch_name_index]) {
                if (ipin_cblock_switch_index != UNDEFINED) {
                    VPR_FATAL_ERROR(VPR_ERROR_ARCH, "Found duplicate switches named '%s'\n",
                                    Arch.ipin_cblock_switch_name[cb_switch_name_index].c_str());
                } else {
                    ipin_cblock_switch_index = iswitch;
                }
            }
        }
        if (ipin_cblock_switch_index == UNDEFINED) {
            VPR_FATAL_ERROR(VPR_ERROR_ARCH, "Failed to find connection block input pin switch named '%s'\n", Arch.ipin_cblock_switch_name[0].c_str());
        }

        //first index in Arch.ipin_cblock_switch_name is related to same die connections
        if (cb_switch_name_index == 0) {
            wire_to_arch_ipin_switch = ipin_cblock_switch_index;
        } else {
            wire_to_arch_ipin_switch_between_dice = ipin_cblock_switch_index;
        }
    }
}

static void alloc_and_load_intra_cluster_resources(bool reachability_analysis) {
    auto& device_ctx = g_vpr_ctx.mutable_device();

    for (auto& physical_type : device_ctx.physical_tile_types) {
        set_root_pin_to_pb_pin_map(&physical_type);
        // Physical number of pins and classes in the clusters start from the number of pins and classes on the cluster
        // to avoid collision between intra-cluster pins and classes with root-level ones
        int physical_pin_offset = physical_type.num_pins;
        int physical_class_offset = (int)physical_type.class_inf.size();
        physical_type.primitive_class_starting_idx = physical_class_offset;
        for (auto& sub_tile : physical_type.sub_tiles) {
            sub_tile.primitive_class_range.resize(sub_tile.capacity.total());
            sub_tile.intra_pin_range.resize(sub_tile.capacity.total());
            for (int sub_tile_inst = 0; sub_tile_inst < sub_tile.capacity.total(); sub_tile_inst++) {
                for (auto logic_block_ptr : sub_tile.equivalent_sites) {
                    int num_classes = (int)logic_block_ptr->primitive_logical_class_inf.size();
                    int num_pins = (int)logic_block_ptr->pin_logical_num_to_pb_pin_mapping.size();
                    int logical_block_idx = logic_block_ptr->index;
                    t_logical_block_type* mutable_logical_block = &device_ctx.logical_block_types[logical_block_idx];
                    VTR_ASSERT(mutable_logical_block == logic_block_ptr);
                    // Continuous ranges are assigned to make passing them more memory-efficient
                    sub_tile.primitive_class_range[sub_tile_inst].insert(
                        std::make_pair(logic_block_ptr, t_class_range(physical_class_offset,
                                                                      physical_class_offset + num_classes - 1)));
                    sub_tile.intra_pin_range[sub_tile_inst].insert(
                        std::make_pair(logic_block_ptr, t_pin_range(physical_pin_offset,
                                                                    physical_pin_offset + num_pins - 1)));
                    add_logical_pin_to_physical_tile(physical_pin_offset, logic_block_ptr, &physical_type);

                    std::vector<t_class> logical_classes = logic_block_ptr->primitive_logical_class_inf;
                    // Change the pin numbers in a class pin list from logical number to physical number
                    std::for_each(logical_classes.begin(), logical_classes.end(),
                                  [&physical_pin_offset](t_class& l_class) {
                                      for (auto& pin : l_class.pinlist) {
                                          pin += physical_pin_offset;
                                      }
                                  });

                    int physical_class_num = physical_class_offset;
                    for (auto& logic_class : logical_classes) {
                        auto result = physical_type.primitive_class_inf.insert(std::make_pair(physical_class_num, logic_class));
                        add_primitive_pin_to_physical_tile(logic_class.pinlist,
                                                           physical_class_num,
                                                           &physical_type);
                        VTR_ASSERT(result.second);
                        if (reachability_analysis && logic_class.type == e_pin_type::RECEIVER) {
                            do_reachability_analysis(&physical_type,
                                                     mutable_logical_block,
                                                     &logic_class,
                                                     physical_class_num);
                        }
                        physical_class_num++;
                    }

                    // Add the number of seen pins and classes to the relevant offsets
                    physical_pin_offset += num_pins;
                    physical_class_offset += num_classes;
                }
            }
        }
    }
}

static void set_root_pin_to_pb_pin_map(t_physical_tile_type* physical_type) {
    for (int sub_tile_idx = 0; sub_tile_idx < (int)physical_type->sub_tiles.size(); sub_tile_idx++) {
        auto& sub_tile = physical_type->sub_tiles[sub_tile_idx];
        int inst_num_pin = sub_tile.num_phy_pins / sub_tile.capacity.total();
        // Later in the code, I've assumed that pins of a subtile are mapped in a continuous fashion to
        // the tile pins - Usage case: vpr_utils.cpp:get_pb_pins
        VTR_ASSERT(sub_tile.sub_tile_to_tile_pin_indices[0] + sub_tile.num_phy_pins - 1 == sub_tile.sub_tile_to_tile_pin_indices[sub_tile.num_phy_pins - 1]);
        for (int sub_tile_pin_num = 0; sub_tile_pin_num < sub_tile.num_phy_pins; sub_tile_pin_num++) {
            for (auto& eq_site : sub_tile.equivalent_sites) {
                t_physical_pin sub_tile_physical_pin = t_physical_pin(sub_tile_pin_num % inst_num_pin);
                int physical_pin_num = sub_tile.sub_tile_to_tile_pin_indices[sub_tile_pin_num];
                auto direct_map = physical_type->tile_block_pin_directs_map.at(eq_site->index).at(sub_tile.index);
                auto find_res = direct_map.find(sub_tile_physical_pin);
                VTR_ASSERT(find_res != direct_map.inverse_end());
                t_logical_pin logical_pin = find_res->second;
                t_pb_graph_pin* pb_pin = eq_site->pin_logical_num_to_pb_pin_mapping.at(logical_pin.pin);

                auto map_find_res = physical_type->on_tile_pin_num_to_pb_pin.find(physical_pin_num);
                if (map_find_res == physical_type->on_tile_pin_num_to_pb_pin.end()) {
                    physical_type->on_tile_pin_num_to_pb_pin.insert(std::make_pair(physical_pin_num,
                                                                                   std::unordered_map<t_logical_block_type_ptr, t_pb_graph_pin*>()));
                }
                auto insert_res = physical_type->on_tile_pin_num_to_pb_pin.at(physical_pin_num).insert(std::make_pair(eq_site, pb_pin));
                VTR_ASSERT(insert_res.second);
            }
        }
    }
}

static void add_logical_pin_to_physical_tile(int physical_pin_offset,
                                             t_logical_block_type_ptr logical_block_ptr,
                                             t_physical_tile_type* physical_type) {
    for (auto logical_pin_pair : logical_block_ptr->pin_logical_num_to_pb_pin_mapping) {
        auto pin_logical_num = logical_pin_pair.first;
        auto pb_pin = logical_pin_pair.second;
        physical_type->pin_num_to_pb_pin.insert(std::make_pair(pin_logical_num + physical_pin_offset, pb_pin));
    }
}

static void add_primitive_pin_to_physical_tile(const std::vector<int>& pin_list,
                                               int physical_class_num,
                                               t_physical_tile_type* physical_tile) {
    for (auto pin_num : pin_list) {
        physical_tile->primitive_pin_class.insert(std::make_pair(pin_num, physical_class_num));
    }
}

static void add_intra_tile_switches() {
    auto& device_ctx = g_vpr_ctx.mutable_device();

    std::unordered_map<float, int> pb_edge_delays;

    VTR_ASSERT(device_ctx.all_sw_inf.size() == device_ctx.arch_switch_inf.size());

    for (auto& logical_block : device_ctx.logical_block_types) {
        if (logical_block.is_empty()) {
            continue;
        }
        t_pb_graph_node* pb_graph_node = logical_block.pb_graph_head;

        int switch_type_id = -1;

        std::list<t_pb_graph_node*> pb_graph_node_q;

        pb_graph_node_q.push_back(pb_graph_node);
        while (!pb_graph_node_q.empty()) {
            pb_graph_node = pb_graph_node_q.front();
            pb_graph_node_q.pop_front();
            auto pb_pins = get_mutable_pb_graph_node_pb_pins(pb_graph_node);

            for (t_pb_graph_pin* pb_pin : pb_pins) {
                for (int out_edge_idx = 0; out_edge_idx < pb_pin->num_output_edges; out_edge_idx++) {
                    t_pb_graph_edge* pb_graph_edge = pb_pin->output_edges[out_edge_idx];
                    float max_delay = pb_graph_edge->delay_max;

                    if (pb_edge_delays.find(max_delay) == pb_edge_delays.end()) {
                        switch_type_id = (int)device_ctx.all_sw_inf.size();
                        pb_edge_delays.insert(std::make_pair(max_delay, switch_type_id));
                        t_arch_switch_inf arch_switch_inf = create_internal_arch_sw(max_delay);
                        // AM: In the function that arch_sw to rr_swith remapping takes place, we assumed that the delay of the intra-cluster
                        // switches is fixed, and it is not dependent on the fan-in.
                        VTR_ASSERT_MSG(arch_switch_inf.fixed_Tdel(), "Intra-cluster switch is expected to have a fixed delay");
                        VTR_ASSERT_MSG(arch_switch_inf.buffered(), "Intra-cluster switch is expected to be buffered (isolating)");
                        VTR_ASSERT_MSG(arch_switch_inf.configurable(), "Intra-cluster switch is expected to be configurable");

                        device_ctx.all_sw_inf.insert(std::make_pair(switch_type_id, arch_switch_inf));
                    } else {
                        switch_type_id = pb_edge_delays.at(max_delay);
                    }

                    // The data type of the number of switches is short - We add this assertion to make sure that overflow doesn't happen
                    VTR_ASSERT(switch_type_id <= std::numeric_limits<short>::max());
                    pb_graph_edge->switch_type_idx = switch_type_id;
                }
            }

            t_pb_type* pb_type = pb_graph_node->pb_type;
            for (int mode_num = 0; mode_num < pb_type->num_modes; mode_num++) {
                t_mode* modes = pb_type->modes;
                for (int pb_type_idx = 0; pb_type_idx < modes[mode_num].num_pb_type_children; pb_type_idx++) {
                    t_pb_type* child_pb_type = &modes[mode_num].pb_type_children[pb_type_idx];
                    for (int pb_num = 0; pb_num < child_pb_type->num_pb; pb_num++) {
                        t_pb_graph_node* child_pb_graph_node = &pb_graph_node->child_pb_graph_nodes[mode_num][pb_type_idx][pb_num];
                        pb_graph_node_q.push_back(child_pb_graph_node);
                    }
                }
            }
        }
    }
}

static void do_reachability_analysis(t_physical_tile_type* physical_tile,
                                     t_logical_block_type* logical_block,
                                     t_class* class_inf,
                                     int physical_class_num) {
    VTR_ASSERT(class_inf->type == e_pin_type::RECEIVER);
    std::list<int> pin_list;
    pin_list.insert(pin_list.begin(), class_inf->pinlist.begin(), class_inf->pinlist.end());

    std::set<t_pb_graph_pin*> seen_pb_pins;
    while (!pin_list.empty()) {
        int curr_pin_physical_num = pin_list.front();
        pin_list.pop_front();

        t_pb_graph_pin* curr_pb_graph_pin = get_mutable_pb_pin_from_pin_physical_num(physical_tile, logical_block, curr_pin_physical_num);
        if (curr_pb_graph_pin->port->type != PORTS::IN_PORT) {
            continue;
        } else {
            auto insert_res = seen_pb_pins.insert(curr_pb_graph_pin);
            // Make sure that we are visiting each pin once.
            if (insert_res.second) {
                curr_pb_graph_pin->connected_sinks_ptc.insert(physical_class_num);
                auto driving_pins = get_physical_pin_src_pins(physical_tile,
                                                              logical_block,
                                                              curr_pin_physical_num);
                for (auto driving_pin_physical_num : driving_pins) {
                    // Since we define reachable class as a class which is connected to a pin through a series of IPINs, only IPINs are added to the list
                    if (get_pin_type_from_pin_physical_num(physical_tile, driving_pin_physical_num) == e_pin_type::RECEIVER) {
                        pin_list.push_back(driving_pin_physical_num);
                    }
                }
            }
        }
    }
}