mods based on Vaughn's comments

Author: KA7E

vpr/src/base/echo_files.cpp

@@ -80,6 +80,9 @@ void alloc_and_load_echo_file_info() {
     //Packing
     setEchoFileName(E_ECHO_CLUSTERS, "clusters.echo");
 
+    //Legalizer
+    setEchoFileName(E_ECHO_FLAT_PLACE, "post_legalizer_flat_placement.echo");
+
     //Intra-block routing
     setEchoFileName(E_ECHO_INTRA_LB_FAILED_ROUTE, "intra_lb_failed_route.echo");
 

vpr/src/base/echo_files.h

@@ -16,6 +16,9 @@ enum e_echo_files {
     //Packing
     E_ECHO_CLUSTERS,
 
+    //Legalizer
+    E_ECHO_FLAT_PLACE,
+
     // Intra-block routing
     E_ECHO_INTRA_LB_FAILED_ROUTE,
 

vpr/src/base/load_flat_place.cpp

@@ -44,10 +44,10 @@ void print_flat_placement(const char* flat_place_file) {
 }
 
 /* ingests and legalizes a flat placement file  */
-bool load_flat_placement(t_vpr_setup& vpr_setup, const char* architecture_id) {
+bool load_flat_placement(t_vpr_setup& vpr_setup, const t_arch& arch) {
     VTR_LOG("load_flat_placement(); when implemented, this function:");
     VTR_LOG("\n\tLoads flat placement file: %s, ", vpr_setup.FileNameOpts.FlatPlaceFile.c_str());
-    VTR_LOG("\n\tArch id: %s, ", architecture_id);
+    VTR_LOG("\n\tArch id: %s, ", arch.architecture_id);
     VTR_LOG("\n\tPrints clustered netlist file: %s, ", vpr_setup.FileNameOpts.NetFile.c_str());
     VTR_LOG("\n\tPrints fix clusters file: %s\n", vpr_setup.FileNameOpts.write_constraints_file.c_str());
 

vpr/src/base/load_flat_place.h

@@ -11,6 +11,6 @@ void print_flat_placement(const char* flat_place_file);
 /**
  * @brief A function that loads and legalizes a flat placement file
  */
-bool load_flat_placement(t_vpr_setup& vpr_setup, const char* archi_id);
+bool load_flat_placement(t_vpr_setup& vpr_setup, const t_arch& arch);
 
 #endif

vpr/src/base/read_options.cpp

@@ -1311,7 +1311,7 @@ argparse::ArgumentParser create_arg_parser(const std::string& prog_name, t_optio
         .default_value("off");
 
     stage_grp.add_argument<bool, ParseOnOff>(args.do_legalize, "--legalize")
-        .help("Legalize a flat placement")
+        .help("Legalize a flat placement, i.e. reconstruct and place clusters based on a flat placement file, which lists cluster and intra-cluster placement coordinates for each primitive.")
         .action(argparse::Action::STORE_TRUE)
         .default_value("off");
 
@@ -1596,7 +1596,7 @@ argparse::ArgumentParser create_arg_parser(const std::string& prog_name, t_optio
         .show_in(argparse::ShowIn::HELP_ONLY);
 
     file_grp.add_argument(args.FlatPlaceFile, "--flat_place_file")
-        .help("Path to flat placement file")
+        .help("Path to input flat placement file")
         .show_in(argparse::ShowIn::HELP_ONLY);
 
     file_grp.add_argument(args.PlaceFile, "--place_file")
@@ -1638,14 +1638,13 @@ argparse::ArgumentParser create_arg_parser(const std::string& prog_name, t_optio
 
     file_grp.add_argument(args.write_constraints_file, "--write_fix_clusters")
         .help(
-            "Output file containing fixed locations of legalized input clusters.")
+            "Output file containing fixed locations of legalized input clusters - does not include clusters without placement coordinates; this file is used during post-legalization placement in order to hold input placement coordinates fixed while VPR places legalizer-generated orphan clusters.")
         .default_value("fix_clusters.out")
         .show_in(argparse::ShowIn::HELP_ONLY);
 
     file_grp.add_argument(args.write_flat_place_file, "--write_flat_place")
         .help(
-            "VPR's placement solution in flat placement file format.")
-        .default_value("flat_place.out")
+            "VPR's (or reconstructed external) placement solution in flat placement file format; this file lists cluster and intra-cluster placement coordinates for each atom and can be used to reconstruct a clustering and placement solution.")
         .show_in(argparse::ShowIn::HELP_ONLY);
 
     file_grp.add_argument(args.read_router_lookahead, "--read_router_lookahead")

vpr/src/base/read_place.cpp

@@ -331,7 +331,7 @@ void print_place(const char* net_file,
     if (!place_ctx.block_locs.empty()) { //Only if placement exists
         for (auto blk_id : cluster_ctx.clb_nlist.blocks()) {
             // if block is not placed, skip (useful for printing legalizer output)
-            if (!is_place_file && (place_ctx.block_locs[blk_id].loc.x == -1)) {
+            if (!is_place_file && (place_ctx.block_locs[blk_id].loc.x == INVALID_X)) {
                 continue;
             }
             fprintf(fp, "%s\t", cluster_ctx.clb_nlist.block_pb(blk_id)->name);

vpr/src/base/read_place.h

@@ -22,6 +22,10 @@ void read_constraints(const char* constraints_file);
  * @param is_place_file: defaults to true. If false, does not print file header; this is useful if
  *                       the output will be used as a constraints file. If is_place_file is false,
  *                       net_file and net_id parameters are not used and can be set to nullptr.
+ *                       Note: if false, only placed clusters are printed - clusters without
+ *                       placement coordinates (e.g. orphan clusters created during legalization
+ *                       will not be included; this file is used as a placement constraints
+ *                       file when running placement in order to place orphan clusters.
  */
 void print_place(const char* net_file,
                  const char* net_id,

vpr/src/base/vpr_api.cpp

@@ -615,24 +615,8 @@ bool vpr_pack_flow(t_vpr_setup& vpr_setup, const t_arch& arch) {
             // generate a .net file by legalizing an input flat placement file
             if (packer_opts.load_flat_placement) {
 
-                // set up the device grid for the legalizer
-                auto& device_ctx = g_vpr_ctx.mutable_device();
-                device_ctx.arch = &arch;
-                device_ctx.grid = create_device_grid(vpr_setup.device_layout, arch.grid_layouts);
-
-                // load and legalize flat placement file, print .net and fix clusters files
-                status = load_flat_placement(vpr_setup, arch.architecture_id);
-                if (!status) {
-                    return status;
-                }
-
-                // reset the device grid
-                device_ctx.grid.clear();
-
-                // if running placement, use the fix clusters file produced by the legalizer
-                if (vpr_setup.PlacerOpts.doPlacement) {
-                    vpr_setup.PlacerOpts.constraints_file = vpr_setup.FileNameOpts.write_constraints_file;
-                }
+                //Load and legalizer flat placement file
+                vpr_load_flat_placement(vpr_setup, arch);
 
                 //Load the result from the .net file
                 vpr_load_packing(vpr_setup, arch);
@@ -747,6 +731,37 @@ void vpr_load_packing(t_vpr_setup& vpr_setup, const t_arch& arch) {
     }
 }
 
+bool vpr_load_flat_placement(t_vpr_setup& vpr_setup, const t_arch& arch) {
+
+    // set up the device grid for the legalizer
+    auto& device_ctx = g_vpr_ctx.mutable_device();
+    device_ctx.arch = &arch;
+    device_ctx.grid = create_device_grid(vpr_setup.device_layout, arch.grid_layouts);
+    if (device_ctx.grid.get_num_layers() > 1) {
+        VPR_FATAL_ERROR(VPR_ERROR_PACK, "Legalizer currently only supports single layer devices.\n");
+    }
+
+    // load and legalize flat placement file, print .net and fix clusters files
+    bool status = load_flat_placement(vpr_setup, arch);
+    if (!status) {
+        return status;
+    }
+
+    // echo flat placement (orphan clusters will have -1 for X, Y, subtile coordinates)
+    if (getEchoEnabled() && isEchoFileEnabled(E_ECHO_FLAT_PLACE)) {
+        print_flat_placement(getEchoFileName(E_ECHO_FLAT_PLACE));
+    }
+
+    // reset the device grid
+    device_ctx.grid.clear();
+
+    // if running placement, use the fix clusters file produced by the legalizer
+    if (vpr_setup.PlacerOpts.doPlacement) {
+        vpr_setup.PlacerOpts.constraints_file = vpr_setup.FileNameOpts.write_constraints_file;
+    }
+    return true;
+}
+
 bool vpr_place_flow(const Netlist<>& net_list, t_vpr_setup& vpr_setup, const t_arch& arch) {
     VTR_LOG("\n");
     const auto& placer_opts = vpr_setup.PlacerOpts;
@@ -775,6 +790,13 @@ bool vpr_place_flow(const Netlist<>& net_list, t_vpr_setup& vpr_setup, const t_a
                                         placer_opts.floorplan_num_horizontal_partitions, placer_opts.floorplan_num_vertical_partitions);
     }
 
+    // Write out a flat placement file if the option is specified
+    // A flat placement file includes cluster and intra-cluster placement coordinates for
+    // each primitive and can be used to reconstruct a clustering and placement solution.
+    if (!filename_opts.write_flat_place_file.empty()) {
+        print_flat_placement(vpr_setup.FileNameOpts.write_flat_place_file.c_str());
+    }
+
     return true;
 }
 

vpr/src/base/vpr_api.h

@@ -65,6 +65,9 @@ bool vpr_pack(t_vpr_setup& vpr_setup, const t_arch& arch);
 ///@brief Loads a previous packing
 void vpr_load_packing(t_vpr_setup& vpr_setup, const t_arch& arch);
 
+///@brief Reconstructs a packing and placement solution from a flat placement file
+bool vpr_load_flat_placement(t_vpr_setup& vpr_setup, const t_arch& arch);
+
 /* Placement */
 
 ///@brief Perform, load or skip the placement stage

vpr/src/base/vpr_types.h

@@ -715,6 +715,9 @@ struct hash<t_pl_offset> {
 };
 } // namespace std
 
+/// @brief Sentinel value for indicating that a block does not have a valid x location, used to check whether a block has been placed
+static constexpr int INVALID_X = -1;
+
 /**
  * @brief A placement location coordinate
  *