Merge pull request #1817 from verilog-to-routing/refactor_init_place_for_floorplanning

Refactor init place for floorplanning

Author: vaughnbetz

vpr/src/place/grid_tile_lookup.cpp

@@ -0,0 +1,143 @@
+#include "grid_tile_lookup.h"
+
+void GridTileLookup::initialize_grid_tile_matrices() {
+    auto& device_ctx = g_vpr_ctx.device();
+
+    //Will store the max number of tile locations for each logical block type
+    max_placement_locations.resize(device_ctx.logical_block_types.size());
+
+    for (const auto& type : device_ctx.logical_block_types) {
+        vtr::NdMatrix<int, 2> type_count({device_ctx.grid.width(), device_ctx.grid.height()});
+        fill_type_matrix(&type, type_count);
+        block_type_matrices.push_back(type_count);
+    }
+}
+
+void GridTileLookup::fill_type_matrix(t_logical_block_type_ptr block_type, vtr::NdMatrix<int, 2>& type_count) {
+    auto& device_ctx = g_vpr_ctx.device();
+
+    int num_rows = device_ctx.grid.height();
+    int num_cols = device_ctx.grid.width();
+
+    /*
+     * Iterating through every location on the grid to store the number of subtiles of
+     * the correct type at each location. For each location, we store the cumulative
+     * number of tiles of the type up to that location - meaning we store the number of
+     * subtiles at the location, plus the number of subtiles at the locations above and to
+     * the right of it.
+     */
+    for (int i_col = type_count.dim_size(0) - 1; i_col >= 0; i_col--) {
+        for (int j_row = type_count.dim_size(1) - 1; j_row >= 0; j_row--) {
+            auto& tile = device_ctx.grid[i_col][j_row].type;
+            type_count[i_col][j_row] = 0;
+
+            if (is_tile_compatible(tile, block_type)) {
+                for (const auto& sub_tile : tile->sub_tiles) {
+                    if (is_sub_tile_compatible(tile, block_type, sub_tile.capacity.low)) {
+                        type_count[i_col][j_row] = sub_tile.capacity.total();
+                    }
+                }
+            }
+
+            if (i_col < num_cols - 1) {
+                type_count[i_col][j_row] += type_count[i_col + 1][j_row];
+            }
+            if (j_row < num_rows - 1) {
+                type_count[i_col][j_row] += type_count[i_col][j_row + 1];
+            }
+            if (i_col < (num_cols - 1) && j_row < (num_rows - 1)) {
+                type_count[i_col][j_row] -= type_count[i_col + 1][j_row + 1];
+            }
+        }
+    }
+
+    //The total number of subtiles for the block type will be at [0][0]
+    max_placement_locations[block_type->index] = type_count[0][0];
+}
+
+vtr::NdMatrix<int, 2>& GridTileLookup::get_type_grid(t_logical_block_type_ptr block_type) {
+    return block_type_matrices[block_type->index];
+}
+
+int GridTileLookup::total_type_tiles(t_logical_block_type_ptr block_type) {
+    return max_placement_locations[block_type->index];
+}
+
+/*
+ * This routine uses pre-computed values from the grids for each block type to get the number of grid tiles
+ * covered by a region.
+ * For a region with no subtiles specified, the number of grid tiles can be calculated by adding
+ * and subtracting four values from within/at the edge of the region.
+ * The region with subtile case is taken care of by a helper routine, region_with_subtile_count().
+ */
+int GridTileLookup::region_tile_count(const Region& reg, t_logical_block_type_ptr block_type) {
+    vtr::Rect<int> reg_rect = reg.get_region_rect();
+    int subtile = reg.get_sub_tile();
+
+    int xmin = reg_rect.xmin();
+    int ymin = reg_rect.ymin();
+    int xmax = reg_rect.xmax();
+    int ymax = reg_rect.ymax();
+    auto& type_grid = block_type_matrices[block_type->index];
+
+    int xdim = type_grid.dim_size(0);
+    int ydim = type_grid.dim_size(1);
+
+    int num_tiles = 0;
+
+    if (subtile == NO_SUBTILE) {
+        num_tiles = type_grid[xmin][ymin];
+
+        if ((ymax + 1) < ydim) {
+            num_tiles -= type_grid[xmin][ymax + 1];
+        }
+
+        if ((xmax + 1) < xdim) {
+            num_tiles -= type_grid[xmax + 1][ymin];
+        }
+
+        if ((xmax + 1) < xdim && (ymax + 1) < ydim) {
+            num_tiles += type_grid[xmax + 1][ymax + 1];
+        }
+    } else {
+        num_tiles = region_with_subtile_count(reg, block_type);
+    }
+
+    return num_tiles;
+}
+
+/*
+ * This routine is for the subtile specified case; an O(region_size) scan needs to be done to check whether each grid
+ * location in the region is compatible for the block at the subtile specified.
+ */
+int GridTileLookup::region_with_subtile_count(const Region& reg, t_logical_block_type_ptr block_type) {
+    auto& device_ctx = g_vpr_ctx.device();
+    int num_sub_tiles = 0;
+    vtr::Rect<int> reg_rect = reg.get_region_rect();
+    int subtile = reg.get_sub_tile();
+
+    int xmin = reg_rect.xmin();
+    int ymin = reg_rect.ymin();
+    int xmax = reg_rect.xmax();
+    int ymax = reg_rect.ymax();
+
+    for (int i = xmax; i >= xmin; i--) {
+        for (int j = ymax; j >= ymin; j--) {
+            auto& tile = device_ctx.grid[i][j].type;
+            if (is_sub_tile_compatible(tile, block_type, subtile)) {
+                num_sub_tiles++;
+            }
+        }
+    }
+
+    return num_sub_tiles;
+}
+
+void GridTileLookup::print_type_matrix(vtr::NdMatrix<int, 2>& type_count) {
+    for (int i_col = type_count.dim_size(0) - 1; i_col >= 0; i_col--) {
+        for (int j_row = type_count.dim_size(1) - 1; j_row >= 0; j_row--) {
+            VTR_LOG("%d ", type_count[i_col][j_row]);
+        }
+        VTR_LOG("\n");
+    }
+}

vpr/src/place/grid_tile_lookup.h

@@ -0,0 +1,49 @@
+/*
+ * This class is used to store a grid for each logical block type that stores the cumulative number of subtiles
+ * for that type available at each location in the grid. The cumulative number of subtiles is the subtiles at the
+ * location plus the subtiles available at the grid locations above and to the right of the locations.
+ * Having these grids allows for O(1) lookups about the number of subtiles available for a given type of block
+ * in a rectangular region.
+ * This lookup class is used during initial placement when sorting blocks by the size of their floorplan constraint
+ * regions.
+ */
+#ifndef VPR_SRC_PLACE_GRID_TILE_LOOKUP_H_
+#define VPR_SRC_PLACE_GRID_TILE_LOOKUP_H_
+
+#include "place_util.h"
+#include "globals.h"
+
+class GridTileLookup {
+  public:
+    vtr::NdMatrix<int, 2>& get_type_grid(t_logical_block_type_ptr block_type);
+
+    void initialize_grid_tile_matrices();
+
+    void fill_type_matrix(t_logical_block_type_ptr block_type, vtr::NdMatrix<int, 2>& type_count);
+
+    void print_type_matrix(vtr::NdMatrix<int, 2>& type_count);
+
+    int region_tile_count(const Region& reg, t_logical_block_type_ptr block_type);
+
+    int region_with_subtile_count(const Region& reg, t_logical_block_type_ptr block_type);
+
+    int total_type_tiles(t_logical_block_type_ptr block_type);
+
+  private:
+    /*
+     * Stores the cumulative total of subtiles available at each location in the grid for each block type.
+     * Therefore, the length of the vector will be the number of logical block types. To access the cumulative
+     * number of subtiles at a location, you would use block_type_matrices[iblock_type][x][y] - this would
+     * give the number of placement locations that are at, or above and to the right of the given [x,y] for
+     * the given block type.
+     */
+    std::vector<vtr::NdMatrix<int, 2>> block_type_matrices;
+
+    /*
+     * Stores the total number of placement locations (i.e. compatible subtiles) for each block type.
+     * To access the max_placement locations for a particular block type, use max_placement_locations[block_type->index]
+     */
+    std::vector<int> max_placement_locations;
+};
+
+#endif /* VPR_SRC_PLACE_GRID_TILE_LOOKUP_H_ */