Merge pull request #1652 from Pinata-Consulting/cts-args-env-vars-2

cts: add CTS_ARGS env var to override CTS arguments

Author: maliberty

docs/user/FlowVariables.md

@@ -166,6 +166,7 @@ Note:
 
 | Variable              | Description                                                                                                  |
 |-----------------------|--------------------------------------------------------------------------------------------------------------|
+| `CTS_ARGS`            | Override `clock_tree_synthesis` arguments                           |
 | `CTS_BUF_CELL`        | The buffer cell used in the clock tree.                                                                      |
 | `FILL_CELLS`          | Fill cells are used to fill empty sites.    								                                   |
 | `HOLD_SLACK_MARGIN`   | Specifies a time margin for the slack when fixing hold violations. This option allow you to overfix.         |

flow/scripts/cts.tcl

@@ -24,21 +24,24 @@ proc save_progress {stage} {
   write_sdc $::env(RESULTS_DIR)/$stage.sdc
 }
 
+set cts_args [list -root_buf "$::env(CTS_BUF_CELL)" -buf_list "$::env(CTS_BUF_CELL)" \
+          -sink_clustering_enable \
+          -sink_clustering_size $cluster_size \
+          -sink_clustering_max_diameter $cluster_diameter \
+          -balance_levels]
+
 if {[info exist ::env(CTS_BUF_DISTANCE)]} {
-  clock_tree_synthesis -root_buf "$::env(CTS_BUF_CELL)" -buf_list "$::env(CTS_BUF_CELL)" \
-                      -sink_clustering_enable \
-                      -sink_clustering_size $cluster_size \
-                      -sink_clustering_max_diameter $cluster_diameter \
-                      -distance_between_buffers "$::env(CTS_BUF_DISTANCE)" \
-                      -balance_levels
-} else {
-  clock_tree_synthesis -root_buf "$::env(CTS_BUF_CELL)" -buf_list "$::env(CTS_BUF_CELL)" \
-                      -sink_clustering_enable \
-                      -sink_clustering_size $cluster_size \
-                      -sink_clustering_max_diameter $cluster_diameter \
-                      -balance_levels
+  lappend cts_args -distance_between_buffers "$::env(CTS_BUF_DISTANCE)"
+}
+
+if {[info exist ::env(CTS_ARGS)]} {
+  set cts_args $::env(CTS_ARGS)
 }
 
+puts "clock_tree_synthesis [join $cts_args " "]"
+
+clock_tree_synthesis {*}$cts_args
+
 if {[info exist ::env(CTS_SNAPSHOTS)]} {
   save_progress 4_1_pre_repair_clock_nets
 }