Improved exception for recursive aliases.

src/main/java/dk/camelot64/kickc/model/VariableReferenceInfos.java

@@ -137,6 +137,52 @@ public class VariableReferenceInfos {
       this.stmtDefinedVars = stmtDefinedVars;
       this.stmtReferencedVars = stmtReferencedVars;
       this.symbolVarReferences = symbolVarReferences;
+
+   }
+
+   public String getSizeInfo() {
+      StringBuilder sizeInfo = new StringBuilder();
+      if(blockReferencedVars!=null) {
+         sizeInfo.append("blockReferencedVars " + blockReferencedVars.size() + " labels ");
+         int sub = 0;
+         for(Collection<VariableRef> variableRefs : blockReferencedVars.values()) {
+            sub += variableRefs.size();
+         }
+         sizeInfo.append(" " + sub + " varrefs" + "\n");
+      }
+      if(blockUsedVars!=null) {
+         sizeInfo.append("blockUsedVars " + blockUsedVars.size() + " labels ");
+         int sub = 0;
+         for(Collection<VariableRef> variableRefs : blockUsedVars.values()) {
+            sub += variableRefs.size();
+         }
+         sizeInfo.append(" " + sub + " varrefs" + "\n");
+      }
+      {
+         sizeInfo.append("stmtDefinedVars " + stmtDefinedVars.size() + " ints ");
+         int sub = 0;
+         for(Collection<VariableRef> variableRefs : stmtDefinedVars.values()) {
+            sub += variableRefs.size();
+         }
+         sizeInfo.append(" " + sub + " varrefs" + "\n");
+      }
+      {
+         sizeInfo.append("stmtReferencedVars " + stmtReferencedVars.size() + " ints ");
+         int sub = 0;
+         for(Collection<VariableRef> variableRefs : stmtReferencedVars.values()) {
+            sub += variableRefs.size();
+         }
+         sizeInfo.append(" " + sub + " varrefs" + "\n");
+      }
+      {
+         sizeInfo.append("symbolVarReferences " + symbolVarReferences.size() + " SymbolVariableRefs ");
+         int sub = 0;
+         for(Collection<ReferenceToSymbolVar> value : symbolVarReferences.values()) {
+            sub += value.size();
+         }
+         sizeInfo.append(" " + sub + " ReferenceToSymbolVars" + "\n");
+      }
+      return sizeInfo.toString();
    }
 
    /**

src/main/java/dk/camelot64/kickc/passes/AliasReplacer.java

@@ -38,7 +38,7 @@ public class AliasReplacer implements ProgramValueHandler {
    @Override
    public void execute(ProgramValue programValue, Statement currentStmt, ListIterator<Statement> stmtIt, ControlFlowBlock currentBlock) {
       if(programValue.get() != null) {
-         Value replacement = getReplacement(programValue.get(), aliases);
+         Value replacement = getReplacement(programValue.get(), aliases, 0);
          if(replacement != null) {
             // System.out.println("Replacing "+programValue.get() + " with " +replacement + " in " +currentStmt);
             programValue.set(replacement);
@@ -55,11 +55,21 @@ public class AliasReplacer implements ProgramValueHandler {
     * @param rValue The RValue to find an alias for
     * @return The alias to use. Null if no alias exists.
     */
-   private static RValue getReplacement(Value rValue, Map<? extends SymbolRef, ? extends RValue> aliases) {
+   private static RValue getReplacement(Value rValue, Map<? extends SymbolRef, ? extends RValue> aliases, int depth) {
+      if(depth>50) {
+         StringBuilder aliasList = new StringBuilder();
+         Value rVal = rValue;
+         do {
+            aliasList.append(rVal.toString()).append(" > ");
+            rVal = aliases.get(rVal);
+         } while(rVal!=rValue);
+         aliasList.append(rVal.toString());
+         throw new InternalError("Error! Recursive aliases: "+aliasList);
+      }
       if(rValue instanceof SymbolRef) {
          RValue alias = aliases.get(rValue);
          if(alias != null) {
-            RValue replacement = getReplacement(alias, aliases);
+            RValue replacement = getReplacement(alias, aliases, depth+1);
             if(replacement != null) {
                return replacement;
             } else {

src/main/java/dk/camelot64/kickc/passes/calcs/PassNCalcVariableReferenceInfos.java

@@ -101,7 +101,11 @@ public class PassNCalcVariableReferenceInfos extends PassNCalcBase<VariableRefer
                   }
                });
       }
-      return new VariableReferenceInfos(blockReferencedVars, blockUsedVars, stmtReferenced, stmtDefined, symbolVarReferences);
+      VariableReferenceInfos variableReferenceInfos = new VariableReferenceInfos(blockReferencedVars, blockUsedVars, stmtReferenced, stmtDefined, symbolVarReferences);
+      if(getLog().isVerboseSSAOptimize()) {
+         getLog().append(variableReferenceInfos.getSizeInfo());
+      }
+      return variableReferenceInfos;
    }
 
    /**