Implemented phi function completion loop.

src/dk/camelot64/kickc/icl/PassGenerateSingleStaticAssignmentForm.java

@@ -21,12 +21,16 @@ public class PassGenerateSingleStaticAssignmentForm {
    public void generate() {
       versionAllAssignments();
       versionAllUses();
+      boolean done = false;
+      do {
+         System.out.println("Completing Phi functions...");
+         done = completePhiFunctions();
+      } while (!done);
    }
 
 
-   /**
+
-    * Version all non-versioned non-intermediary being assigned a value.
+   /** Version all non-versioned non-intermediary being assigned a value. */
-    */
    private void versionAllAssignments() {
       for (ControlFlowBlock block : controlFlowGraph.getAllBlocks()) {
          for (Statement statement : block.getStatements()) {
@@ -43,9 +47,7 @@ public class PassGenerateSingleStaticAssignmentForm {
       }
    }
 
-   /**
+   /** Version all uses of non-versioned non-intermediary variables */
-    * Version all uses of non-versioned non-intermediary variables
-    */
    private void versionAllUses() {
       for (ControlFlowBlock block : controlFlowGraph.getAllBlocks()) {
          // Newest version of variables in the block.
@@ -82,6 +84,14 @@ public class PassGenerateSingleStaticAssignmentForm {
 
    }
 
+   /**
+    * Find and return the latest version of an rValue (if it is a non-versioned symbol).
+    * If a version is needed and no version is found a new version is created as a phi-function.
+    * @param rValue The rValue to examine
+    * @param blockVersions The current version defined in the block for each symbol.
+    * @param blockNewPhis New versions to be created as phi-functions. Modified if a new phi-function needs to be created.
+    * @return Null if the rValue does not need versioning. The versioned symbol to use if it does.
+    */
    private Symbol findOrCreateVersion(RValue rValue, Map<Symbol, Symbol> blockVersions, Map<Symbol, Symbol> blockNewPhis) {
       Symbol version = null;
       if (rValue instanceof Symbol) {
@@ -103,5 +113,94 @@ public class PassGenerateSingleStaticAssignmentForm {
       return version;
    }
 
+   /** Look through all new phi-functions and fill out their parameters.
+    * @return true if all phis were completely filled out.
+    * false if new phis were added , meaning another iteration is needed.
+    * */
+   private boolean completePhiFunctions() {
+      Map<ControlFlowBlock, Map<Symbol, Symbol>> newPhis = new HashMap<>();
+      Map<Symbol, Map<Symbol, Symbol>> symbolMap = buildSymbolMap();
+      for (ControlFlowBlock block : this.controlFlowGraph.getAllBlocks()) {
+         for (Statement statement : block.getStatements()) {
+            if (statement instanceof StatementPhi) {
+               StatementPhi phi = (StatementPhi) statement;
+               if (phi.getPreviousVersions().isEmpty()) {
+                  Symbol versioned = phi.getlValue();
+                  Symbol unversioned = versioned.getVersionOf();
+                  for (ControlFlowBlock predecessor : block.getPredecessors()) {
+                     Symbol previousSymbol = symbolMap.get(predecessor.getLabel()).get(unversioned);
+                     if (previousSymbol == null) {
+                        // No previous symbol found in predecessor block. Look in new a phi functions.
+                        Map<Symbol, Symbol> predecessorNewPhis = newPhis.get(predecessor);
+                        if (predecessorNewPhis == null) {
+                           predecessorNewPhis = new HashMap<>();
+                           newPhis.put(predecessor, predecessorNewPhis);
+                        }
+                        previousSymbol = predecessorNewPhis.get(unversioned);
+                        if (previousSymbol == null) {
+                           // No previous symbol found in predecessor block. Add a new phi function to the predecessor.
+                           previousSymbol = symbols.createVersion(unversioned);
+                           predecessorNewPhis.put(unversioned, previousSymbol);
+                        }
+                     }
+                     phi.addPreviousVersion(predecessor, previousSymbol);
+                  }
+               }
+            }
+         }
+      }
+      // Ads new phi functions to blocks
+      for (ControlFlowBlock block : controlFlowGraph.getAllBlocks()) {
+         Map<Symbol, Symbol> blockNewPhis = newPhis.get(block);
+         if(blockNewPhis!=null) {
+            for (Symbol symbol : blockNewPhis.keySet()) {
+               block.addPhiStatement(blockNewPhis.get(symbol));
+            }
+         }
+      }
+      return (newPhis.size()==0);
+   }
+
+   /**
+    * Builds a map of all which versions each symbol has in each block.
+    * Maps Control Flow Block Label -> ( Unversioned Symbol -> Versioned Symbol) for all relevant symbols.
+    */
+   private Map<Symbol, Map<Symbol, Symbol>> buildSymbolMap() {
+      Map<Symbol, Map<Symbol, Symbol>> symbolMap = new HashMap<>();
+      for (ControlFlowBlock block : this.controlFlowGraph.getAllBlocks()) {
+         for (Statement statement : block.getStatements()) {
+            if(statement instanceof StatementAssignment) {
+               StatementAssignment assignment = (StatementAssignment) statement;
+               LValue lValue = assignment.getlValue();
+               if(lValue instanceof Symbol) {
+                  Symbol symbol = (Symbol) lValue;
+                  if(symbol.isVersioned()) {
+                     Symbol label = block.getLabel();
+                     Symbol unversioned = symbol.getVersionOf();
+                     Symbol versioned = symbol;
+                     Map<Symbol, Symbol> blockMap = symbolMap.get(label);
+                     if(blockMap == null) {
+                        blockMap = new HashMap<>();
+                        symbolMap.put(label, blockMap);
+                     }
+                     blockMap.put(unversioned, versioned);
+                  }
+               }
+            } else if(statement instanceof StatementPhi) {
+               StatementPhi phi = (StatementPhi) statement;
+               Symbol versioned = phi.getlValue();
+               Symbol unversioned = versioned.getVersionOf();
+               Symbol label = block.getLabel();
+               Map<Symbol, Symbol> blockMap = symbolMap.get(label);
+               if(blockMap == null) {
+                  blockMap = new HashMap<>();
+                  symbolMap.put(label, blockMap);
+               }
+               blockMap.put(unversioned, versioned);
+            }
+         }
+      } return symbolMap;
+   }
+
 
 }

src/dk/camelot64/kickc/icl/StatementPhi.java

@@ -15,23 +15,46 @@ public class StatementPhi implements Statement {
    private Symbol lValue;
 
    /** The previous version of the symbol from predeccesor control blocks. */
-   private List<Symbol> previousVersions;
+   private List<PreviousSymbol> previousVersions;
-
 
    public StatementPhi(Symbol lValue) {
       this.lValue = lValue;
       this.previousVersions = new ArrayList<>();
    }
 
-   public LValue getlValue() {
+   /**
+    * A previous version of the symbol that the phi function might take its value from.
+    * Which value is chosen depends on which block transition was made.
+    */
+   public static class PreviousSymbol {
+      private ControlFlowBlock block;
+      private Symbol symbol;
+
+      public PreviousSymbol(ControlFlowBlock block, Symbol symbol) {
+         this.block = block;
+         this.symbol = symbol;
+      }
+
+      public ControlFlowBlock getBlock() {
+         return block;
+      }
+
+      public Symbol getSymbol() {
+         return symbol;
+      }
+
+
+   }
+
+   public Symbol getlValue() {
       return lValue;
    }
 
-   public void addPreviousVersion(Symbol previousVersion) {
+   public void addPreviousVersion(ControlFlowBlock block, Symbol symbol) {
-      previousVersions.add(previousVersion);
+      previousVersions.add(new PreviousSymbol(block, symbol));
    }
 
-   public List<Symbol> getPreviousVersions() {
+   public List<PreviousSymbol> getPreviousVersions() {
       return previousVersions;
    }
 
@@ -39,8 +62,8 @@ public class StatementPhi implements Statement {
    public String toString() {
       StringBuilder out = new StringBuilder();
       out.append(lValue + " ← " + "phi(");
-      for (Symbol previousVersion : previousVersions) {
+      for (PreviousSymbol previousSymbol : previousVersions) {
-         out.append(" "+previousVersion.toString());
+         out.append(" "+previousSymbol.getBlock().getLabel().getName()+"/"+previousSymbol.getSymbol().getName());
       }
       out.append(" )");
       return out.toString();

src/dk/camelot64/kickc/icl/SymbolManager.java

@@ -1,7 +1,6 @@
 package dk.camelot64.kickc.icl;
 
-import java.util.LinkedHashMap;
+import java.util.*;
-import java.util.Map;
 
 /**
  * Manages symbols (variables, labels)
@@ -58,7 +57,10 @@ public class SymbolManager {
    @Override
    public String toString() {
       StringBuffer out = new StringBuffer();
-      for (String name : symbols.keySet()) {
+      Set<String> names = symbols.keySet();
+      List<String> sortedNames = new ArrayList<>(names);
+      Collections.sort(sortedNames);
+      for (String name : sortedNames) {
          Symbol symbol = symbols.get(name);
          out.append(symbol.toString() + "\n");
       }