Warnings for aliases during codegen

The code generator gave the wrong variable indexes for aliases that
were not replaced in the backend. This prints some warnings or errors
for these cases so we can either fix the code (or replace the code
generator to handle aliases better).

Belonging to [master]:
  - #2076
  - OpenModelica/OpenModelica-testsuite#810

Author: sjoelund

Compiler/SimCode/SimCodeMain.mo

@@ -566,7 +566,6 @@ protected
       end if;
       res := (true,SimCodeUtil.getFunctionIndex());
     else
-      ErrorExt.moveMessagesToParentThread();
     end try;
   end runTplWriteFile;
 
@@ -581,7 +580,6 @@ protected
       Tpl.tplCallWithFailErrorNoArg(func);
       res := (true,SimCodeUtil.getFunctionIndex());
     else
-      ErrorExt.moveMessagesToParentThread();
     end try;
   end runTpl;
 
@@ -599,7 +597,6 @@ protected
       func();
       res := (true,SimCodeUtil.getFunctionIndex());
     else
-      ErrorExt.moveMessagesToParentThread();
     end try;
   end runToStr;
 
@@ -611,7 +608,10 @@ protected
   algorithm
     (res as (b,_)) := func();
     if not b then
-      print(System.dladdr(func) + " failed\n");
+      Error.addInternalError(System.dladdr(func) + " failed\n", sourceInfo());
+    end if;
+    if ErrorExt.getNumMessages() > 0 then
+      ErrorExt.moveMessagesToParentThread();
     end if;
   end runCodegenFunc;
 

Compiler/SimCode/SimCodeUtil.mo

@@ -399,29 +399,29 @@ algorithm
     if debug then execStat("simCode: createModelInfo and variables"); end if;
 
     //build labels
-     if(boolAnd(ifcpp,Flags.getConfigBool(Flags.LABELED_REDUCTION))) then
-     Flags.setConfigBool(Flags.GENERATE_LABELED_SIMCODE,true);
+    if(boolAnd(ifcpp,Flags.getConfigBool(Flags.LABELED_REDUCTION))) then
+      Flags.setConfigBool(Flags.GENERATE_LABELED_SIMCODE,true);
     end if;
 
-	if(ifcpp) then
-	if Flags.getConfigBool(Flags.GENERATE_LABELED_SIMCODE) then
+    if(ifcpp) then
+      if Flags.getConfigBool(Flags.GENERATE_LABELED_SIMCODE) then
         (allEquations,modelInfo) := ReduceDAE.buildLabels(allEquations,modelInfo,{},args);
         //Flags.set(Flags.REDUCE_DAE,true);
-		if debug then execStat("ReduceDAE: buildLabels"); end if;
-		end if;
-	end if;
+        if debug then execStat("ReduceDAE: buildLabels"); end if;
+      end if;
+    end if;
 
     tmpSimVars := modelInfo.vars;
 
     //reduce terms
-	if(ifcpp) then
-	if Flags.getConfigBool(Flags.REDUCE_TERMS) then
+    if(ifcpp) then
+      if Flags.getConfigBool(Flags.REDUCE_TERMS) then
         (allEquations,modelInfo) := ReduceDAE.reduceTerms(allEquations,modelInfo,args);
         Flags.setConfigBool(Flags.REDUCE_TERMS, false);
-        _:=Flags.disableDebug(Flags.REDUCE_DAE);
-		if debug then execStat("ReduceDAE: reduceTerms"); end if;
-		end if;
-	end if;
+        Flags.disableDebug(Flags.REDUCE_DAE);
+        if debug then execStat("ReduceDAE: reduceTerms"); end if;
+      end if;
+    end if;
     // external objects
     extObjInfo := createExtObjInfo(shared);
 
@@ -13319,6 +13319,19 @@ algorithm
     case (cref, SimCode.SIMCODE(crefToSimVarHT = crefToSimVarHT) )
       equation
         sv = BaseHashTable.get(cref, crefToSimVarHT);
+        sv = match sv.aliasvar
+          case SimCodeVar.NOALIAS() then sv;
+          /* The C++ runtime generates a different set of variables... */
+          case _ guard Config.simCodeTarget() == "Cpp" then sv;
+          case SimCodeVar.ALIAS(varName=cref)
+            algorithm
+              Error.addSourceMessage(Error.COMPILER_WARNING, {getInstanceName() + " got an alias variable " + ComponentReference.printComponentRefStr(inCref) + " to " + ComponentReference.printComponentRefStr(cref) + ", but before code generation these should have been removed"}, sv.source.info);
+           then cref2simvar(cref, simCode);
+          case SimCodeVar.NEGATEDALIAS(varName=cref)
+            algorithm
+              Error.addSourceMessage(Error.INTERNAL_ERROR, {getInstanceName() + " got a negated alias variable " + ComponentReference.printComponentRefStr(inCref) + " to " + ComponentReference.printComponentRefStr(cref) + ", but before code generation these should have been removed"}, sv.source.info);
+            then fail();
+        end match;
       then sv;
 
     case (_, _)