open_synth: make it work with OpenSTA

Modify scripts so that make open_synth can work with OpenSTA,
this simplifies reporting issues. Turnaround times on real
test cases is long, so it is nice to have this debugged
in ORFS.

To examine timing of a design using OpenSTA:

make OPENROAD_EXE=../tools/install/OpenROAD/bin/sta open_synth

To create an OpenSTA standalone issue, run:

make OPENROAD_EXE=../tools/install/OpenROAD/bin/sta open_issue

Tinker with run-*.sh script, create a small script,
source scripts/sta-synth.tcl and create test-case.

Author: oharboe

flow/scripts/load.tcl

@@ -6,14 +6,18 @@ proc load_design {design_file sdc_file} {
   # Read liberty files
   source $::env(SCRIPTS_DIR)/read_liberty.tcl
 
+  # OpenSTA does not have read_lef
+  set got_lef [expr [llength [info commands read_lef]] > 0]
   # Read design files
   set ext [file extension $design_file]
   if {$ext == ".v"} {
-    read_lef $::env(TECH_LEF)
-    read_lef $::env(SC_LEF)
-    if {[env_var_exists_and_non_empty ADDITIONAL_LEFS]} {
-      foreach lef $::env(ADDITIONAL_LEFS) {
-        read_lef $lef
+    if {$got_lef} {
+      read_lef $::env(TECH_LEF)
+      read_lef $::env(SC_LEF)
+      if {[env_var_exists_and_non_empty ADDITIONAL_LEFS]} {
+        foreach lef $::env(ADDITIONAL_LEFS) {
+          read_lef $lef
+        }
       }
     }
     read_verilog $::env(RESULTS_DIR)/$design_file
@@ -24,9 +28,12 @@ proc load_design {design_file sdc_file} {
     error "Unrecognized input file $design_file"
   }
 
-  # Read SDC file
   read_sdc $::env(RESULTS_DIR)/$sdc_file
 
+  if {!$got_lef} {
+    return
+  }
+
   if [file exists $::env(PLATFORM_DIR)/derate.tcl] {
     log_cmd source $::env(PLATFORM_DIR)/derate.tcl
   }

flow/scripts/sta-synth.tcl

@@ -1,2 +1,14 @@
 source $::env(SCRIPTS_DIR)/load.tcl
 load_design 1_synth.v 1_synth.sdc
+
+if {[env_var_equals GUI_TIMING 1]} {
+  puts "GUI_TIMING=1 reading timing, takes a little while for large designs..."
+  set openroad [expr [llength [info commands ord::openroad_version]] > 0]
+
+  if {$openroad && [gui::enabled]} {
+    gui::select_chart "Endpoint Slack"
+    log_cmd gui::update_timing_report
+  } else {
+    report_checks
+  }
+}