Keep variable names in generated sources

core/src/main/java/org/teavm/ast/optimization/UnusedVariableEliminator.java

@@ -60,6 +60,10 @@ class UnusedVariableEliminator extends RecursiveVisitor {
             indexes[variables[var]] = index;
             reorderedVariables.add(variableNodes[var]);
         }
+        VariableNode node = variableNodes[var];
+        if (node.getName() != null) {
+            reorderedVariables.get(index).setName(node.getName());
+        }
         return index;
     }
 

core/src/main/java/org/teavm/backend/wasm/render/WasmCRenderer.java

@@ -137,10 +137,25 @@ public class WasmCRenderer {
     }
 
     private void renderFunction(WasmFunction function) {
-        line(functionDeclaration(function) + " {");
+        WasmCRenderingVisitor visitor = new WasmCRenderingVisitor(function.getResult(),
+                function.getLocalVariables().size(), function.getModule());
+
+        StringBuilder declaration = new StringBuilder();
+        renderFunctionModifiers(declaration, function);
+        declaration.append(WasmCRenderingVisitor.mapType(function.getResult())).append(' ');
+        declaration.append(function.getName()).append('(');
+        for (int i = 0; i < function.getParameters().size(); ++i) {
+            if (i > 0) {
+                declaration.append(", ");
+            }
+            declaration.append(WasmCRenderingVisitor.mapType(function.getParameters().get(i)));
+            WasmLocal var = function.getLocalVariables().get(i);
+            declaration.append(' ').append(visitor.getVariableName(var));
+        }
+        declaration.append(") {");
+        line(declaration.toString());
         indent();
 
-        WasmCRenderingVisitor visitor = new WasmCRenderingVisitor(function.getResult(), function.getModule());
         List<WasmLocal> variables = function.getLocalVariables().subList(function.getParameters().size(),
                 function.getLocalVariables().size());
         for (WasmLocal variable : variables) {
@@ -175,29 +190,28 @@ public class WasmCRenderer {
 
     private String functionDeclaration(WasmFunction function) {
         StringBuilder sb = new StringBuilder();
-        if (function.getImportName() != null) {
+        renderFunctionModifiers(sb, function);
-            sb.append("extern ");
-        } else if (function.getExportName() == null) {
-            sb.append("static ");
-        }
         sb.append(WasmCRenderingVisitor.mapType(function.getResult())).append(' ');
         sb.append(function.getName()).append("(");
-        WasmCRenderingVisitor visitor = new WasmCRenderingVisitor(function.getResult(), function.getModule());
         for (int i = 0; i < function.getParameters().size(); ++i) {
             if (i > 0) {
                 sb.append(", ");
             }
             sb.append(WasmCRenderingVisitor.mapType(function.getParameters().get(i)));
-            WasmLocal local = i < function.getLocalVariables().size()
-                    ? function.getLocalVariables().get(i)
-                    : null;
-            sb.append(" ").append(local != null ? visitor.getVariableName(local) : "var_" + i);
         }
         sb.append(")");
 
         return sb.toString();
     }
 
+    private static void renderFunctionModifiers(StringBuilder sb, WasmFunction function) {
+        if (function.getImportName() != null) {
+            sb.append("extern ");
+        } else if (function.getExportName() == null) {
+            sb.append("static ");
+        }
+    }
+
     @Override
     public String toString() {
         return out.toString();

core/src/main/java/org/teavm/backend/wasm/render/WasmCRenderingVisitor.java

@@ -18,8 +18,10 @@ package org.teavm.backend.wasm.render;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import org.teavm.backend.wasm.model.WasmFunction;
 import org.teavm.backend.wasm.model.WasmLocal;
 import org.teavm.backend.wasm.model.WasmModule;
@@ -67,8 +69,11 @@ class WasmCRenderingVisitor implements WasmExpressionVisitor {
     private int blockIndex;
     private WasmType functionType;
     private WasmModule module;
+    private String[] localVariableNames;
+    private Set<String> usedVariableNames = new HashSet<>();
 
-    WasmCRenderingVisitor(WasmType functionType, WasmModule module) {
+    WasmCRenderingVisitor(WasmType functionType, int variableCount, WasmModule module) {
+        localVariableNames = new String[variableCount];
         this.functionType = functionType;
         this.module = module;
     }
@@ -1036,9 +1041,23 @@ class WasmCRenderingVisitor implements WasmExpressionVisitor {
     }
 
     String getVariableName(WasmLocal local) {
+        String result = localVariableNames[local.getIndex()];
+        if (result == null) {
             if (local.getName() != null) {
-            return local.getName();
+                result = local.getName();
+            } else {
+                result = "localVar" + local.getIndex();
             }
-        return "var_" + local.getIndex();
+            if (!usedVariableNames.add(result)) {
+                String base = result;
+                int suffix = 1;
+                while (!usedVariableNames.add(base + suffix)) {
+                    ++suffix;
+                }
+                result = base + suffix;
+            }
+            localVariableNames[local.getIndex()] = result;
+        }
+        return result;
     }
 }

core/src/main/java/org/teavm/model/PreOptimizingClassHolderSource.java

@@ -37,7 +37,7 @@ public class PreOptimizingClassHolderSource implements ClassHolderSource {
                 return null;
             }
             for (MethodHolder method : cls.getMethods()) {
-                new GlobalValueNumbering().optimize(method, method.getProgram());
+                new GlobalValueNumbering(true).optimize(method, method.getProgram());
                 new UnusedVariableElimination().optimize(method, method.getProgram());
             }
             cache.put(name, cls);

core/src/main/java/org/teavm/model/optimization/GlobalValueNumbering.java

@@ -34,12 +34,17 @@ public class GlobalValueNumbering implements MethodOptimization {
     private Program program;
     private int currentBlockIndex;
     private DominatorTree domTree;
+    private boolean namesPreserved;
 
     private static class KnownValue {
         int value;
         int location;
     }
 
+    public GlobalValueNumbering(boolean namesPreserved) {
+        this.namesPreserved = namesPreserved;
+    }
+
     @Override
     public boolean optimize(MethodReader method, Program program) {
         boolean affected = false;
@@ -66,28 +71,6 @@ public class GlobalValueNumbering implements MethodOptimization {
             int v = stack[--top];
             currentBlockIndex = v;
             BasicBlock block = program.basicBlockAt(v);
-            /*for (int i = 0; i < block.getPhis().size(); ++i) {
-                Phi phi = block.getPhis().get(i);
-                int sharedValue = -2;
-                for (Incoming incoming : phi.getIncomings()) {
-                    int value = map[incoming.getValue().getIndex()];
-                    incoming.setValue(program.variableAt(value));
-                    if (sharedValue != -2 && sharedValue != incoming.getValue().getIndex()) {
-                        sharedValue = -1;
-                    } else {
-                        sharedValue = incoming.getValue().getIndex();
-                    }
-                }
-                if (sharedValue != -1) {
-                    if (sharedValue != -2) {
-                        AssignInstruction assignInsn = new AssignInstruction();
-                        assignInsn.setReceiver(phi.getReceiver());
-                        assignInsn.setAssignee(program.variableAt(sharedValue));
-                        block.getInstructions().add(0, assignInsn);
-                    }
-                    block.getPhis().remove(i--);
-                }
-            }*/
 
             if (block.getExceptionVariable() != null) {
                 int var = map[block.getExceptionVariable().getIndex()];
@@ -149,21 +132,9 @@ public class GlobalValueNumbering implements MethodOptimization {
                 stack[top++] = succ;
             }
         }
-
-        String[] debugNames = new String[program.variableCount()];
-        for (int i = 0; i < program.variableCount(); ++i) {
-            debugNames[i] = program.variableAt(i).getDebugName();
-            program.variableAt(i).setDebugName(null);
-        }
         for (int i = 0; i < map.length; ++i) {
             if (map[i] != i) {
-                Variable mapVar = program.variableAt(map[i]);
-                if (debugNames[i] != null && mapVar.getDebugName() == null) {
-                    mapVar.setDebugName(debugNames[i]);
-                }
                 program.deleteVariable(i);
-            } else {
-                program.variableAt(i).setDebugName(debugNames[i]);
             }
         }
 
@@ -174,19 +145,38 @@ public class GlobalValueNumbering implements MethodOptimization {
 
     private void bind(int var, String value) {
         String name = program.variableAt(map[var]).getDebugName();
-        if (name == null) {
+        if (name == null || namesPreserved) {
             name = "";
         }
 
         KnownValue known = knownValues.get(name + ":" + value);
-        if (known != null && domTree.dominates(known.location, currentBlockIndex) && known.value != var) {
+        if (known == null) {
+            known = knownValues.get(":" + value);
+        }
+        boolean namesCompatible = !namesPreserved;
+        if (!namesCompatible && known != null) {
+            String knownName = program.variableAt(known.value).getDebugName();
+            if (knownName == null) {
+                knownName = "";
+            }
+            namesCompatible = knownName.isEmpty() || name.isEmpty() || knownName.equals(name);
+        }
+        if (known != null && domTree.dominates(known.location, currentBlockIndex) && known.value != var
+                && namesCompatible) {
             eliminate = true;
             map[var] = known.value;
+            if (!name.isEmpty()) {
+                program.variableAt(known.value).setDebugName(name);
+                knownValues.put(name + ":" + value, known);
+            }
         } else {
             known = new KnownValue();
             known.location = currentBlockIndex;
             known.value = var;
             knownValues.put(name + ":" + value, known);
+            if (!name.isEmpty()) {
+                knownValues.put(":" + value, known);
+            }
         }
     }
 
@@ -498,6 +488,16 @@ public class GlobalValueNumbering implements MethodOptimization {
 
         @Override
         public void visit(AssignInstruction insn) {
+            if (namesPreserved) {
+                if (insn.getReceiver().getDebugName() != null && insn.getAssignee().getDebugName() != null) {
+                    if (!insn.getAssignee().getDebugName().equals(insn.getReceiver().getDebugName())) {
+                        return;
+                    }
+                }
+            }
+            if (insn.getReceiver().getDebugName() != null) {
+                insn.getAssignee().setDebugName(insn.getReceiver().getDebugName());
+            }
             map[insn.getReceiver().getIndex()] = map[insn.getAssignee().getIndex()];
             eliminate = true;
         }

core/src/main/java/org/teavm/model/util/GraphColorer.java

@@ -15,6 +15,7 @@
  */
 package org.teavm.model.util;
 
+import java.util.ArrayList;
 import java.util.BitSet;
 import java.util.List;
 import org.teavm.common.IntegerArray;
@@ -23,11 +24,12 @@ import org.teavm.common.MutableGraphNode;
 
 class GraphColorer {
     public void colorize(List<MutableGraphNode> graph, int[] colors) {
-        colorize(graph, colors, new int[graph.size()]);
+        colorize(graph, colors, new int[graph.size()], new String[graph.size()]);
     }
 
-    public void colorize(List<MutableGraphNode> graph, int[] colors, int[] categories) {
+    public void colorize(List<MutableGraphNode> graph, int[] colors, int[] categories, String[] names) {
         IntegerArray colorCategories = new IntegerArray(graph.size());
+        List<String> colorNames = new ArrayList<>();
         for (int i = 0; i < colors.length; ++i) {
             int color = colors[i];
             if (colors[i] < 0) {
@@ -36,7 +38,11 @@ class GraphColorer {
             while (colorCategories.size() <= color) {
                 colorCategories.add(-1);
             }
+            while (colorNames.size() <= color) {
+                colorNames.add(null);
+            }
             colorCategories.set(color, categories[i]);
+            colorNames.set(color, names[i]);
         }
         BitSet usedColors = new BitSet();
         for (int v : getOrdering(graph)) {
@@ -56,11 +62,19 @@ class GraphColorer {
                 color = usedColors.nextClearBit(color);
                 while (colorCategories.size() <= color) {
                     colorCategories.add(-1);
+                    colorNames.add(null);
                 }
                 int category = colorCategories.get(color);
-                if (category < 0 || category == categories[v]) {
+                String name = colorNames.get(color);
+                if ((category < 0 || category == categories[v])
+                        && (name == null || names[v] == null || name.equals(names[v]))) {
                     colors[v] = color;
                     colorCategories.set(color, categories[v]);
+                    if (names[v] != null) {
+                        colorNames.set(color, names[v]);
+                    } else {
+                        names[v] = name;
+                    }
                     break;
                 }
                 ++color;

core/src/main/java/org/teavm/model/util/RegisterAllocator.java

@@ -67,13 +67,33 @@ public class RegisterAllocator {
             maxClass = Math.max(maxClass, cls + 1);
         }
         int[] categories = getVariableCategories(program, method.getReference());
+        String[] names = getVariableNames(program);
         int[] classCategories = new int[maxClass];
+        String[] classNames = new String[maxClass];
         for (int i = 0; i < categories.length; ++i) {
             classCategories[classArray[i]] = categories[i];
+            classNames[classArray[i]] = names[i];
         }
-        colorer.colorize(interferenceGraph, colors, classCategories);
+        colorer.colorize(interferenceGraph, colors, classCategories, classNames);
+
+        int maxColor = 0;
         for (int i = 0; i < colors.length; ++i) {
             program.variableAt(i).setRegister(colors[i]);
+            maxColor = Math.max(maxClass, colors[i]);
+        }
+
+        String[] namesByRegister = new String[maxColor];
+        for (int i = 0; i < colors.length; ++i) {
+            Variable var = program.variableAt(i);
+            if (var.getDebugName() != null && var.getRegister() >= 0) {
+                namesByRegister[var.getRegister()] = var.getDebugName();
+            }
+        }
+        for (int i = 0; i < colors.length; ++i) {
+            Variable var = program.variableAt(i);
+            if (var.getRegister() >= 0) {
+                var.setDebugName(namesByRegister[var.getRegister()]);
+            }
         }
 
         for (int i = 0; i < program.basicBlockCount(); ++i) {
@@ -95,6 +115,14 @@ public class RegisterAllocator {
         return categories;
     }
 
+    private String[] getVariableNames(ProgramReader program) {
+        String[] names = new String[program.variableCount()];
+        for (int i = 0; i < names.length; ++i) {
+            names[i] = program.variableAt(i).getDebugName();
+        }
+        return names;
+    }
+
     private static void joinClassNodes(List<MutableGraphNode> graph, DisjointSet classes) {
         int sz = graph.size();
         for (int i = 0; i < sz; ++i) {
@@ -257,13 +285,15 @@ public class RegisterAllocator {
             BasicBlock block = program.basicBlockAt(i);
             mapper.apply(block);
         }
-        String[] originalNames = new String[program.variableCount()];
+        String[] originalNames = getVariableNames(program);
         for (int i = 0; i < program.variableCount(); ++i) {
-            Variable var = program.variableAt(i);
+            program.variableAt(i).setDebugName(null);
-            originalNames[i] = var.getDebugName();
         }
         for (int i = 0; i < program.variableCount(); ++i) {
-            program.variableAt(varMap[i]).setDebugName(originalNames[i]);
+            Variable var = program.variableAt(varMap[i]);
+            if (originalNames[i] != null) {
+                var.setDebugName(originalNames[i]);
+            }
         }
     }
 

core/src/main/java/org/teavm/vm/TeaVM.java

@@ -375,7 +375,6 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
             }
         }
 
-        removeDebugNames(classSet);
         optimize(classSet);
         if (wasCancelled()) {
             return;
@@ -451,25 +450,6 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
         }
     }
 
-    private void removeDebugNames(ListableClassHolderSource classes) {
-        if (optimizationLevel == TeaVMOptimizationLevel.SIMPLE) {
-            return;
-        }
-        for (String className : classes.getClassNames()) {
-            ClassHolder cls = classes.get(className);
-            for (MethodHolder method : cls.getMethods()) {
-                if (method.getProgram() != null) {
-                    for (int i = 0; i < method.getProgram().variableCount(); ++i) {
-                        method.getProgram().variableAt(i).setDebugName(null);
-                    }
-                }
-            }
-            if (wasCancelled()) {
-                return;
-            }
-        }
-    }
-
     private void optimize(ListableClassHolderSource classSource) {
         for (String className : classSource.getClassNames()) {
             ClassHolder cls = classSource.get(className);
@@ -521,7 +501,7 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
             optimizations.add(new LoopInversion());
             optimizations.add(new LoopInvariantMotion());
         }
-        optimizations.add(new GlobalValueNumbering());
+        optimizations.add(new GlobalValueNumbering(optimizationLevel == TeaVMOptimizationLevel.SIMPLE));
         if (optimizationLevel.ordinal() >= TeaVMOptimizationLevel.ADVANCED.ordinal()) {
             optimizations.add(new ConstantConditionElimination());
             optimizations.add(new RedundantJumpElimination());

tools/cli/src/main/java/org/teavm/cli/TeaVMRunner.java

@@ -64,6 +64,8 @@ public final class TeaVMRunner {
                 .create("m"));
         options.addOption(OptionBuilder
                 .withDescription("optimization level (1-3)")
+                .hasArg()
+                .withArgName("number")
                 .create("O"));
         options.addOption(OptionBuilder
                 .withArgName("separate|merge|none")