Fix scalability issue in NFUnitCheck

Set the cref hashtable to an appropriate size at the start.

Also re-added the `-d=-frontEndUnitCheck` flag which was previously
not used in the new frontend always enabling the unit checking. This
has the default set to true with the ability to disable the phase.

Belonging to [master]:
  - OpenModelica/OMCompiler#1978
  - OpenModelica/OpenModelica-testsuite#764

Compiler/FrontEnd/Inst.mo

@@ -329,7 +329,7 @@ algorithm
     case (cache,ih,cdecls as _::_,path)
       equation
         (outCache,outEnv,outIH,outDAElist) = instantiateClass_dispatch(cache,ih,cdecls,path,doSCodeDep);
-        if Flags.isSet(Flags.NF_UNITCHECK) then
+        if Flags.isSet(Flags.OLD_FE_UNITCHECK) then
             NFUnitCheck.checkUnits(outDAElist,FCore.getFunctionTree(outCache));
         end if;
       then

Compiler/NFFrontEnd/NFUnitCheck.mo

@@ -52,13 +52,16 @@ protected
   NFHashTableStringToUnit.HashTable HtS2U;
   NFHashTableUnitToString.HashTable HtU2S;
 algorithm
+  if not Flags.isSet(Flags.NF_UNITCHECK) then
+    return;
+  end if;
   try
     (elts1, elts2) := DAEUtil.splitDAEIntoVarsAndEquations(inDAE);
     varlist := GetVarList(elts1);
     eqlist := GetElementList(elts2);
     functionlist := DAEUtil.getFunctionList(func);
 
-    HtCr2U1 := NFHashTableCrToUnit.emptyHashTableSized(2053);
+    HtCr2U1 := NFHashTableCrToUnit.emptyHashTableSized(Util.nextPrime(integer(10+1.4*listLength(varlist))));
     HtS2U := NFUnit.getKnownUnits();
     HtU2S := NFUnit.getKnownUnitsInverse();
 
@@ -68,7 +71,6 @@ algorithm
 
     // new instantiation
     //((HtCr2U1, HtS2U, HtU2S)) := List.fold(varlist, convertUnitString2unit, (HtCr2U1, HtS2U, HtU2S));
-
     // old instantiation
     ((HtCr2U1, HtS2U, HtU2S)) := List.fold(varlist, convertUnitString2unit_old, (HtCr2U1, HtS2U, HtU2S));
     HtCr2U2 := BaseHashTable.copy(HtCr2U1);
@@ -1368,18 +1370,18 @@ protected function parse "author: lochel"
   output NFHashTableStringToUnit.HashTable outHtS2U = inHtS2U;
   output NFHashTableUnitToString.HashTable outHtU2S = inHtU2S;
 algorithm
+  if inUnitString == "" then
+    outUnit := NFUnit.MASTER({inCref});
+    return;
+  end if;
   try
-  outUnit := BaseHashTable.get(inUnitString, inHtS2U);
+    outUnit := BaseHashTable.get(inUnitString, inHtS2U);
   else
-    outUnit := matchcontinue(inUnitString)
-      case ""
-      then NFUnit.MASTER({inCref});
-
-      case _
-      then NFUnit.parseUnitString(inUnitString, inHtS2U);
-
-    else NFUnit.UNKNOWN(inUnitString);
-    end matchcontinue;
+    try
+      outUnit := NFUnit.parseUnitString(inUnitString, inHtS2U);
+    else
+      outUnit := NFUnit.UNKNOWN(inUnitString);
+    end try;
     outHtS2U := addUnit2HtS2U((inUnitString, outUnit), outHtS2U);
     outHtU2S := addUnit2HtU2S((inUnitString, outUnit), outHtU2S);
   end try;

Compiler/Util/Flags.mo

@@ -508,7 +508,7 @@ constant DebugFlag PARTITION_INITIALIZATION = DEBUG_FLAG(166, "partitionInitiali
   Util.gettext("This flag controls if partitioning is applied to the initialization system."));
 constant DebugFlag EVAL_PARAM_DUMP = DEBUG_FLAG(167, "evalParameterDump", false,
   Util.gettext("Dumps information for evaluating parameters."));
-constant DebugFlag NF_UNITCHECK = DEBUG_FLAG(168, "frontEndUnitCheck", false,
+constant DebugFlag NF_UNITCHECK = DEBUG_FLAG(168, "frontEndUnitCheck", true,
   Util.gettext("Checks the consistency of units in equation."));
 constant DebugFlag DISABLE_COLORING = DEBUG_FLAG(169, "disableColoring", false,
   Util.gettext("Disables coloring algorithm while spasity detection."));
@@ -522,6 +522,8 @@ constant DebugFlag ALIAS_CONFLICTS = DEBUG_FLAG(173, "aliasConflicts", false,
   Util.gettext("Dumps alias sets with different start or nominal values."));
 constant DebugFlag SUSAN_MATCHCONTINUE_DEBUG = DEBUG_FLAG(174, "susanDebug", false,
   Util.gettext("Makes Susan generate code using try/else to better debug which function broke the expected match semantics."));
+constant DebugFlag OLD_FE_UNITCHECK = DEBUG_FLAG(175, "oldFrontEndUnitCheck", false,
+  Util.gettext("Checks the consistency of units in equation (for the old front-end)."));
 
 // This is a list of all debug flags, to keep track of which flags are used. A
 // flag can not be used unless it's in this list, and the list is checked at
@@ -702,7 +704,8 @@ constant list<DebugFlag> allDebugFlags = {
   WARN_NO_NOMINAL,
   IGNORE_CYCLES,
   ALIAS_CONFLICTS,
-  SUSAN_MATCHCONTINUE_DEBUG
+  SUSAN_MATCHCONTINUE_DEBUG,
+  OLD_FE_UNITCHECK
 };
 
 public