improved node ordering

src/main/java/de/neemann/digital/hdl/model2/HDLCircuit.java

@@ -157,14 +157,6 @@ public class HDLCircuit implements Iterable<HDLNode>, HDLModel.BitProvider, Prin
             if (o.getNet().needsVariable())
                 o.getNet().setIsOutput(o.getName(), o.getNet().getInputs().size() == 1);
 
-        sortNodes();
-    }
-
-    /**
-     * Sorts the nodes
-     */
-    public void sortNodes() {
-        nodes = new NodeSorter(inputs, nodes).sort();
     }
 
     private void handleSplitter(HDLNode node) throws BitsException, HDLException {
@@ -320,7 +312,6 @@ public class HDLCircuit implements Iterable<HDLNode>, HDLModel.BitProvider, Prin
         for (HDLNet n : listOfNets)
             if (n.getName() == null)
                 n.setName(netNaming.createName(n));
-        sortNodes();
         return this;
     }
 
@@ -525,6 +516,7 @@ public class HDLCircuit implements Iterable<HDLNode>, HDLModel.BitProvider, Prin
         apply(new RemoveConstantSignals());
         apply(new MergeConstants());  // under certain circumstances there are still constants
         apply(new NameConstantSignals());
+        apply(new NodeSorterExpressionBased());
         return nameUnnamedSignals();
     }
 

src/main/java/de/neemann/digital/hdl/model2/NodeSorter.java

@@ -1,99 +0,0 @@
-/*
- * Copyright (c) 2018 Helmut Neemann.
- * Use of this source code is governed by the GPL v3 license
- * that can be found in the LICENSE file.
- */
-package de.neemann.digital.hdl.model2;
-
-import java.util.ArrayList;
-import java.util.HashSet;
-
-/**
- * Used to sort the nodes in a more "human typical" order.
- * Sorts the nodes from the input side to the output side.
- */
-public class NodeSorter {
-    private final ArrayList<HDLPort> inputs;
-    private final ArrayList<HDLNode> nodes;
-
-    /**
-     * Creates a new instance.
-     *
-     * @param inputs the initial inputs
-     * @param nodes  the nodes to sort
-     */
-    NodeSorter(ArrayList<HDLPort> inputs, ArrayList<HDLNode> nodes) {
-        this.inputs = inputs;
-        this.nodes = nodes;
-    }
-
-    /**
-     * Performs the sorting and returns a sorted list.
-     *
-     * @return the sorted list
-     */
-    public ArrayList<HDLNode> sort() {
-        HashSet<HDLNet> nets = new HashSet<>();
-        for (HDLPort p : inputs)
-            nets.add(p.getNet());
-
-        ArrayList<HDLNode> newOrder = new ArrayList<>();
-
-        // all nodes without an input at top!
-        for (HDLNode n : nodes)
-            if (n.getInputs().isEmpty()) {
-                newOrder.add(n);
-                for (HDLPort p : n.getOutputs())
-                    if (p.getNet() != null)
-                        nets.add(p.getNet());
-            }
-        nodes.removeAll(newOrder);
-
-        // than a layer sorting
-        while (!nodes.isEmpty()) {
-            ArrayList<HDLNode> layer = new ArrayList<>();
-            for (HDLNode n : nodes) {
-                if (dependsOnlyOn(n, nets))
-                    layer.add(n);
-            }
-
-            if (layer.isEmpty()) {
-                // circular dependency detected
-                for (HDLNode n : nodes)
-                    if (dependsAtLeastAtOne(n, nets))
-                        layer.add(n);
-            }
-
-            if (layer.isEmpty())
-                break;
-
-            newOrder.addAll(layer);
-            nodes.removeAll(layer);
-            for (HDLNode n : layer)
-                for (HDLPort p : n.getOutputs())
-                    if (p.getNet() != null)
-                        nets.add(p.getNet());
-
-        }
-
-        // if there are circular dependencies, keep old order
-        if (!nodes.isEmpty())
-            newOrder.addAll(nodes);
-
-        return newOrder;
-    }
-
-    private boolean dependsOnlyOn(HDLNode n, HashSet<HDLNet> nets) {
-        for (HDLPort p : n.getInputs())
-            if (!p.getNet().isClock() && !nets.contains(p.getNet()))
-                return false;
-        return true;
-    }
-
-    private boolean dependsAtLeastAtOne(HDLNode n, HashSet<HDLNet> nets) {
-        for (HDLPort p : n.getInputs())
-            if (!p.getNet().isClock() && nets.contains(p.getNet()))
-                return true;
-        return false;
-    }
-}

src/main/java/de/neemann/digital/hdl/model2/expression/ExprUsingNet.java

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2018 Helmut Neemann.
+ * Use of this source code is governed by the GPL v3 license
+ * that can be found in the LICENSE file.
+ */
+package de.neemann.digital.hdl.model2.expression;
+
+import de.neemann.digital.hdl.model2.HDLNet;
+
+/**
+ * Implemented by all expressions using a net
+ */
+public interface ExprUsingNet {
+    /**
+     * @return the used net
+     */
+    HDLNet getNet();
+}

src/main/java/de/neemann/digital/hdl/model2/expression/ExprVar.java

@@ -13,7 +13,7 @@ import java.io.IOException;
 /**
  * A reference to a net
  */
-public class ExprVar implements Expression {
+public class ExprVar implements Expression, ExprUsingNet {
     private HDLNet net;
 
     /**
@@ -27,9 +27,7 @@ public class ExprVar implements Expression {
         this.net = net;
     }
 
-    /**
+    @Override
-     * @return the net
-     */
     public HDLNet getNet() {
         return net;
     }

src/main/java/de/neemann/digital/hdl/model2/expression/ExprVarRange.java

@@ -13,7 +13,7 @@ import java.io.IOException;
 /**
  * A reference to a net slice
  */
-public class ExprVarRange implements Expression {
+public class ExprVarRange implements Expression, ExprUsingNet {
     private HDLNet net;
     private final int msb;
     private final int lsb;
@@ -31,9 +31,7 @@ public class ExprVarRange implements Expression {
         this.lsb = lsb;
     }
 
-    /**
+    @Override
-     * @return the net
-     */
     public HDLNet getNet() {
         return net;
     }

src/main/java/de/neemann/digital/hdl/model2/optimizations/NodeSorterExpressionBased.java

@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) 2018 Helmut Neemann.
+ * Use of this source code is governed by the GPL v3 license
+ * that can be found in the LICENSE file.
+ */
+package de.neemann.digital.hdl.model2.optimizations;
+
+import de.neemann.digital.hdl.model2.HDLCircuit;
+import de.neemann.digital.hdl.model2.HDLNet;
+import de.neemann.digital.hdl.model2.HDLNode;
+import de.neemann.digital.hdl.model2.HDLPort;
+import de.neemann.digital.hdl.model2.expression.ExprUsingNet;
+import de.neemann.digital.hdl.model2.expression.Expression;
+import de.neemann.digital.hdl.model2.expression.Visitor;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+
+/**
+ * Used to sort the nodes in a more "human typical" order.
+ * Sorts the nodes from the input side to the output side.
+ */
+public class NodeSorterExpressionBased implements Optimization {
+
+    @Override
+    public void optimize(HDLCircuit circuit) {
+        ArrayList<HDLNode> nodes = circuit.getNodes();
+        ArrayList<HDLNode> nodesAvail = new ArrayList<>(nodes);
+        nodes.clear();
+
+        HashSet<HDLNet> nets = new HashSet<>();
+        for (HDLPort p : circuit.getInputs())
+            nets.add(p.getNet());
+
+
+        // all nodes without an input at top!
+        for (HDLNode n : nodesAvail)
+            if (n.getInputs().isEmpty()) {
+                nodes.add(n);
+                for (HDLPort p : n.getOutputs())
+                    if (p.getNet() != null)
+                        nets.add(p.getNet());
+            }
+        nodesAvail.removeAll(nodes);
+
+        // then a layer sorting
+        while (!nodesAvail.isEmpty()) {
+            ArrayList<HDLNode> layer = new ArrayList<>();
+            for (HDLNode n : nodesAvail) {
+                if (n.traverseExpressions(new DependsOnlyOn(nets)).ok())
+                    layer.add(n);
+            }
+
+            if (layer.isEmpty()) {
+                // circular dependency detected
+                for (HDLNode n : nodesAvail)
+                    if (n.traverseExpressions(new DependsAtLeastOnOneOf(nets)).ok())
+                        layer.add(n);
+            }
+
+            if (layer.isEmpty())
+                break;
+
+            nodes.addAll(layer);
+            nodesAvail.removeAll(layer);
+            for (HDLNode n : layer)
+                for (HDLPort p : n.getOutputs())
+                    if (p.getNet() != null)
+                        nets.add(p.getNet());
+
+        }
+
+        // if there are unsolvable circular dependencies, keep old order
+        if (!nodesAvail.isEmpty())
+            nodes.addAll(nodesAvail);
+    }
+
+    private static final class DependsOnlyOn implements Visitor {
+        private final HashSet<HDLNet> nets;
+        private boolean dependsOnlyOn = true;
+
+        private DependsOnlyOn(HashSet<HDLNet> nets) {
+            this.nets = nets;
+        }
+
+        @Override
+        public void visit(Expression expression) {
+            if (expression instanceof ExprUsingNet) {
+                final HDLNet net = ((ExprUsingNet) expression).getNet();
+                if (!net.isClock() && !nets.contains(net))
+                    dependsOnlyOn = false;
+            }
+        }
+
+        public boolean ok() {
+            return dependsOnlyOn;
+        }
+    }
+
+    private static final class DependsAtLeastOnOneOf implements Visitor {
+        private final HashSet<HDLNet> nets;
+        private boolean dependsAtLeastOnOne = false;
+
+        private DependsAtLeastOnOneOf(HashSet<HDLNet> nets) {
+            this.nets = nets;
+        }
+
+        @Override
+        public void visit(Expression expression) {
+            if (expression instanceof ExprUsingNet) {
+                final HDLNet net = ((ExprUsingNet) expression).getNet();
+                if (!net.isClock() && nets.contains(net))
+                    dependsAtLeastOnOne = true;
+            }
+        }
+
+        public boolean ok() {
+            return dependsAtLeastOnOne;
+        }
+    }
+
+    private boolean dependsOnlyOn(HDLNode n, HashSet<HDLNet> nets) {
+        for (HDLPort p : n.getInputs())
+            if (!p.getNet().isClock() && !nets.contains(p.getNet()))
+                return false;
+        return true;
+    }
+
+    private boolean dependsAtLeastAtOne(HDLNode n, HashSet<HDLNet> nets) {
+        for (HDLPort p : n.getInputs())
+            if (!p.getNet().isClock() && nets.contains(p.getNet()))
+                return true;
+        return false;
+    }
+
+}

src/test/java/de/neemann/digital/hdl/model2/HDLModelTest.java

@@ -10,10 +10,7 @@ import de.neemann.digital.draw.elements.PinException;
 import de.neemann.digital.draw.library.ElementNotFoundException;
 import de.neemann.digital.hdl.model2.clock.ClockIntegratorGeneric;
 import de.neemann.digital.hdl.model2.clock.HDLClockIntegrator;
-import de.neemann.digital.hdl.model2.optimizations.MergeConstants;
+import de.neemann.digital.hdl.model2.optimizations.*;
-import de.neemann.digital.hdl.model2.optimizations.MergeAssignements;
-import de.neemann.digital.hdl.model2.optimizations.NameConstantSignals;
-import de.neemann.digital.hdl.model2.optimizations.ReplaceOneToMany;
 import de.neemann.digital.hdl.printer.CodePrinterStr;
 import de.neemann.digital.integration.ToBreakRunner;
 import junit.framework.TestCase;
@@ -30,6 +27,7 @@ public class HDLModelTest extends TestCase {
     public void testSimple() throws IOException, PinException, HDLException, NodeException, ElementNotFoundException {
         HDLCircuit hdl = getCircuit("dig/hdl/model2/comb.dig", null)
                 .apply(new MergeAssignements())
+                .apply(new NodeSorterExpressionBased())
                 .nameUnnamedSignals();
 
         CodePrinterStr cp = new CodePrinterStr();
@@ -43,14 +41,14 @@ public class HDLModelTest extends TestCase {
                 "    in()\n" +
                 "    out(out:1 defines (s1->1))\n" +
                 "    s1->1 := 1:1\n" +
-                "  node Not\n" +
-                "    in(in:1 reads (A->3))\n" +
-                "    out(out:1 defines (Z_temp->2))\n" +
-                "    Z_temp->2 := NOT A\n" +
                 "  node merged expression\n" +
                 "    in(In_1:1 reads (B->2), in:1 reads (C->2))\n" +
                 "    out(out:1 defines (Y_temp->2))\n" +
                 "    Y_temp->2 := (B OR NOT C)\n" +
+                "  node Not\n" +
+                "    in(in:1 reads (A->3))\n" +
+                "    out(out:1 defines (Z_temp->2))\n" +
+                "    Z_temp->2 := NOT A\n" +
                 "  node merged expression\n" +
                 "    in(In_5:1 reads (Y_temp->2), In_1:1 reads (A->3), In_2:1 reads (C->2), In_1:1 reads (Z_temp->2), In_1:1 reads (B->2))\n" +
                 "    out(out:1 defines (s0->1))\n" +
@@ -220,6 +218,7 @@ public class HDLModelTest extends TestCase {
                 .apply(new MergeAssignements())
                 .apply(new MergeConstants())
                 .apply(new NameConstantSignals())
+                .apply(new NodeSorterExpressionBased())
                 .nameUnnamedSignals();
 
         CodePrinterStr cp = new CodePrinterStr();
@@ -294,6 +293,7 @@ public class HDLModelTest extends TestCase {
         HDLCircuit hdl = getCircuit("dig/hdl/model2/splitter3.dig", null)
                 .apply(new ReplaceOneToMany())
                 .apply(new MergeAssignements())
+                .apply(new NodeSorterExpressionBased())
                 .nameUnnamedSignals();
 
         CodePrinterStr cp = new CodePrinterStr();
@@ -324,6 +324,7 @@ public class HDLModelTest extends TestCase {
         HDLCircuit hdl = getCircuit("dig/hdl/model2/splitter4.dig", null)
                 .apply(new ReplaceOneToMany())
                 .apply(new MergeAssignements())
+                .apply(new NodeSorterExpressionBased())
                 .nameUnnamedSignals();
 
         CodePrinterStr cp = new CodePrinterStr();

src/test/java/de/neemann/digital/hdl/vhdl2/ClockTest.java

@@ -291,7 +291,7 @@ public class ClockTest extends TestCase {
                 new HDLModel(br.getLibrary()),
                 ci);
 
-        c.apply(new MergeAssignements()).nameUnnamedSignals();
+        c.applyDefaultOptimizations();
 
         CodePrinter out = new CodePrinterStr();
         new VHDLCreator(out).printHDLCircuit(c);

src/test/java/de/neemann/digital/hdl/vhdl2/DescriptionTest.java

@@ -29,9 +29,7 @@ public class DescriptionTest extends TestCase {
                 "main"
                 , new HDLModel(br.getLibrary()),
                 null)
-                .apply(new MergeConstants())
+                .applyDefaultOptimizations();
-                .apply(new MergeAssignements())
-                .nameUnnamedSignals();
         CodePrinterStr out = new CodePrinterStr();
         new VHDLCreator(out).printHDLCircuit(circuit);
 

src/test/java/de/neemann/digital/hdl/vhdl2/VHDLGeneratorTest.java

@@ -70,8 +70,8 @@ public class VHDLGeneratorTest extends TestCase {
                 "  signal s0: std_logic;\n" +
                 "  signal Z_temp: std_logic;\n" +
                 "begin\n" +
-                "  Z_temp <= NOT A;\n" +
                 "  Y_temp <= (B OR NOT C);\n" +
+                "  Z_temp <= NOT A;\n"+
                 "  s0 <= ((A OR C) AND (Z_temp OR C) AND '1' AND NOT (B OR C) AND Y_temp);\n" +
                 "  gate0: entity work.DIG_D_FF\n" +
                 "    port map (\n" +