Avoid calling bc, to minimize binaries needed in bazel environment.

In minimal installations, bc might not be available. We already
process the data with awk, so we have everything needed to do the
calculations.

Author: hzeller

place_and_route/private/benchmark.bzl

@@ -71,7 +71,7 @@ def benchmark(ctx, open_road_info):
     ]
     awk_cmds = [
         "area=$(cat {log} | awk '/Design area/ {{ print $3 }}');",
-        "util=$(cat {log} | awk -F '[ %]' '/Design area/ {{ print $5 }}');",
+        "util_fraction=$(cat {log} | awk -F '[ %]' '/Design area/ {{ printf(\"%.3f\", $5 / 100.0); }}');",
         "combos=$(cat {log} | awk '/combinational cell/ {{ print $4 }}');",
         "combos_area=$(cat {log} | awk '/combinational cell/ {{ print $5 }}');",
         "seq=$(cat {log} | awk '/Sequential cell/ {{ print $3 }}');",
@@ -82,10 +82,10 @@ def benchmark(ctx, open_road_info):
         "tbuffs_area=$(cat {log} | awk '/Timing Repair Buffer/ {{ print $4 }}');",
         "inverters=$(cat {log} | awk '/Inverter/ {{ print $2 }}');",
         "inverters_area=$(cat {log} | awk '/Inverter/ {{ print $2 }}');",
-        "wns=$(cat {log} | awk '/wns/ {{ print $2 }}');",
-        "tns=$(cat {log} | awk '/tns/ {{ print $2 }}');",
-        "period=$(cat {log} | awk '/clk  / {{ period=$2; exit }} END {{ print period }}');",
-        "cpl=$(cat {log} | awk '/period_min/ {{ cpl=$4; exit }} END {{ print cpl }}');",
+        "wns_ps=$(cat {log} | awk '/wns/ {{ printf(\"%.0f\", $2 * 1000); }}');",
+        "tns_ps=$(cat {log} | awk '/tns/ {{ printf(\"%.0f\", $2 * 1000); }}');",
+        "period=$(cat {log} | awk '/clk  / {{ period=$2; exit }} END {{ printf(\"%.0f\", period * 1000); }}');",
+        "cpl=$(cat {log} | awk '/period_min/ {{ cpl=$4; exit }} END {{ printf(\"%.0f\", cpl * 1000); }}');",
         "fmax=$(cat {log} | awk '/fmax/ {{ fmax=$7; exit }} END {{ print fmax }}');",
         "tot_pow=$(cat {log} | awk '/^Total / {{ total_power=$5 }} END {{ print total_power }}');",
         "int_pow=$(cat {log} | awk '/^Total / {{ intern_power=$2 }} END {{ print intern_power }}');",
@@ -97,8 +97,7 @@ def benchmark(ctx, open_road_info):
         struct(
             area = struct(
                 cell_area_um2 = "${area:=0}",
-                # Use bc -l to set scale, otherwise XX/100 will evaluate to zero.
-                cell_utilization_fraction = "$(printf %.3f $(bc -l<<<$util/100.0))",
+                cell_utilization_fraction = "${util_fraction:=0}",
                 area_sequentials_um2 = "${seq_area:=0}",
                 area_combinationals_um2 = "${combos_area:=0}",
                 area_buffers_um2 = "${buffs_area:=0}",
@@ -112,11 +111,11 @@ def benchmark(ctx, open_road_info):
                 num_inverters = "${inverters:=0}",
             ),
             performance = struct(
-                clock_period_ps = "$(printf %.0f $(bc<<<$period*1000))",
-                critical_path_ps = "$(printf %.0f $(bc<<<$cpl*1000))",
+                clock_period_ps = "${period:=0}",
+                critical_path_ps = "${cpl:=0}",
                 fmax_ghz = "${fmax:=0}",
-                setup_wns_ps = "$(printf %.0f $(bc<<<$wns*1000))",
-                setup_tns_ps = "$(printf %.0f $(bc<<<$tns*1000))",
+                setup_wns_ps = "${wns_ps:=0}",
+                setup_tns_ps = "${tns_ps:=0}",
             ),
             power = struct(
                 total = struct(