Allow Liberty floats as strings for `voltage_map` and `capacitive_load_unit` (#280)

* Allow Liberty floats as strings for voltage_map and capacitive_load_unit

* Update liberty_float_as_str.lib

* Use valid bool

* Remove unused include

liberty/LibertyReader.cc

@@ -26,6 +26,7 @@
 
 #include <cctype>
 #include <cstdlib>
+#include <string>
 
 #include "EnumNameMap.hh"
 #include "Report.hh"
@@ -873,8 +874,23 @@ LibertyReader::visitCapacitiveLoadUnit(LibertyAttr *attr)
       LibertyAttrValueIterator value_iter(attr->values());
       if (value_iter.hasNext()) {
 	LibertyAttrValue *value = value_iter.next();
+	bool valid = false;
+	float scale;
 	if (value->isFloat()) {
-	  float scale = value->floatValue();
+	  scale = value->floatValue();
+	  valid = true;
+	}
+	else if (value->isString()) {
+	  try {
+	    scale = std::stof(value->stringValue());
+	    valid = true;
+	  }
+	  catch (...) {
+	    valid = false;
+	  }
+	}
+
+	if (valid) {
 	  if (value_iter.hasNext()) {
 	    value = value_iter.next();
 	    if (value->isString()) {
@@ -968,10 +984,24 @@ LibertyReader::visitVoltageMap(LibertyAttr *attr)
 	  const char *supply_name = value->stringValue();
 	  if (value_iter.hasNext()) {
 	    value = value_iter.next();
+            bool valid = false;
+	    float voltage;
 	    if (value->isFloat()) {
-	      float voltage = value->floatValue();
-	      library_->addSupplyVoltage(supply_name, voltage);
+	      voltage = value->floatValue();
+	      valid = true;
 	    }
+	    else if (value->isString()) {
+	      try {
+                voltage = std::stof(value->stringValue());
+                valid = true;
+	      }
+	      catch (...) {
+	        valid = false;
+	      }
+	    }
+
+	    if (valid)
+	      library_->addSupplyVoltage(supply_name, voltage);
 	    else
 	      libWarn(1166, attr, "voltage_map voltage is not a float.");
 	  }

test/liberty_float_as_str.lib

@@ -0,0 +1,55 @@
+library (liberty_float_as_str) {
+  delay_model : "table_lookup";
+  simulation : false;
+  capacitive_load_unit ("1","fF");
+  leakage_power_unit : "1pW";
+  current_unit : "1A";
+  pulling_resistance_unit : "1kohm";
+  time_unit : "1ns";
+  voltage_unit : "1v";
+  library_features : "report_delay_calculation";
+  input_threshold_pct_rise : 50;
+  input_threshold_pct_fall : 50;
+  output_threshold_pct_rise : 50;
+  output_threshold_pct_fall : 50;
+  slew_lower_threshold_pct_rise : 30;
+  slew_lower_threshold_pct_fall : 30;
+  slew_upper_threshold_pct_rise : 70;
+  slew_upper_threshold_pct_fall : 70;
+  slew_derate_from_library : 1.0;
+  nom_process : 1.0;
+  nom_temperature : 85.0;
+  nom_voltage : 0.75;
+  voltage_map ("VDD", "0.65");
+  voltage_map ("VSS", "0");
+  voltage_map ("VCC", "-0.1");
+  voltage_map ("VBB", 0.1);
+  voltage_map ("GND", 0);
+
+  cell (my_inv) {
+    pin (A) {
+      capacitance : 1;
+      direction : "input";
+    }
+    pin (Y) {
+      function : "!A";
+      direction : "output";
+      timing () {
+        related_pin : "A";
+        timing_sense : "negative_unate";
+        cell_rise (scalar) {
+          values ("1");
+        }
+        cell_fall (scalar) {
+          values ("1");
+        }
+        rise_transition (scalar) {
+          values ("1");
+        }
+        fall_transition (scalar) {
+          values ("1");
+        }
+      }
+    }
+  }
+}

test/liberty_float_as_str.ok

@@ -0,0 +1,7 @@
+ time 1ns
+ capacitance 1fF
+ resistance 1kohm
+ voltage 1v
+ current 1A
+ power 1pW
+ distance 1um

test/liberty_float_as_str.tcl

@@ -0,0 +1,3 @@
+# liberty with float as string in voltage_map and capacitive_load_unit
+read_liberty liberty_float_as_str.lib
+report_units

test/regression_vars.tcl

@@ -147,6 +147,7 @@ record_sta_tests {
   liberty_arcs_one2one_2
   liberty_backslash_eol
   liberty_ccsn
+  liberty_float_as_str
   liberty_latch3
   path_group_names
   prima3