AST optimizations and output code minification

teavm-core/src/main/java/org/teavm/javascript/Decompiler.java

@@ -120,6 +120,7 @@ public class Decompiler {
             clsNode.getMethods().add(decompile(method));
         }
         clsNode.getInterfaces().addAll(cls.getInterfaces());
+        clsNode.getModifiers().addAll(mapModifiers(cls.getModifiers()));
         return clsNode;
     }
 
@@ -213,6 +214,7 @@ public class Decompiler {
         }
         Optimizer optimizer = new Optimizer();
         optimizer.optimize(methodNode, method.getProgram());
+        methodNode.getModifiers().addAll(mapModifiers(method.getModifiers()));
         return methodNode;
     }
 
@@ -220,6 +222,8 @@ public class Decompiler {
         Set<NodeModifier> result = EnumSet.noneOf(NodeModifier.class);
         if (modifiers.contains(ElementModifier.STATIC)) {
             result.add(NodeModifier.STATIC);
+        } else if (modifiers.contains(ElementModifier.INTERFACE)) {
+            result.add(NodeModifier.INTERFACE);
         }
         return result;
     }

teavm-core/src/main/java/org/teavm/javascript/Optimizer.java

@@ -37,6 +37,8 @@ public class Optimizer {
         UnusedVariableEliminator unusedEliminator = new UnusedVariableEliminator(paramCount, method.getVariables());
         method.getBody().acceptVisitor(unusedEliminator);
         method.getVariables().subList(unusedEliminator.lastIndex, method.getVariables().size()).clear();
+        RedundantLabelEliminator labelEliminator = new RedundantLabelEliminator();
+        method.getBody().acceptVisitor(labelEliminator);
         for (int i = 0; i < method.getVariables().size(); ++i) {
             method.getVariables().set(i, i);
         }

teavm-core/src/main/java/org/teavm/javascript/OptimizingVisitor.java

@@ -28,6 +28,10 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
     private ReadWriteStatsBuilder stats;
     Map<IdentifiedStatement, Integer> referencedStatements = new HashMap<>();
     private List<Statement> resultSequence;
+    private int[] variableDecl;
+    private List<Boolean> invocations;
+    private int lastMethodCall;
+    private boolean hasMethodCall;
 
     public OptimizingVisitor(ReadWriteStatsBuilder stats) {
         this.stats = stats;
@@ -118,22 +122,27 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
         if (stats.reads[index] != 1 || stats.writes[index] != 1) {
             return;
         }
-        if (resultSequence.isEmpty()) {
+        int declIndex = variableDecl[index];
+        if (declIndex < 0 || declIndex >= lastMethodCall) {
             return;
         }
-        Statement last = resultSequence.get(resultSequence.size() - 1);
-        if (!(last instanceof AssignmentStatement)) {
-            return;
+        if (invocations.get(declIndex)) {
+            for (int i = lastMethodCall - 1; i > declIndex; --i) {
+                if (invocations.get(i)) {
+                    return;
+                }
+            }
         }
-        AssignmentStatement assignment = (AssignmentStatement)last;
-        if (!(assignment.getLeftValue() instanceof VariableExpr)) {
-            return;
-        }
-        VariableExpr var = (VariableExpr)assignment.getLeftValue();
-        if (var.getIndex() == index) {
-            resultSequence.remove(resultSequence.size() - 1);
-            assignment.getRightValue().acceptVisitor(this);
+        for (int i = declIndex; i < lastMethodCall; ++i) {
+            if (invocations.get(i)) {
+                lastMethodCall = i;
+                break;
+            }
         }
+        AssignmentStatement decl = (AssignmentStatement)resultSequence.get(declIndex);
+        resultSequence.set(declIndex, null);
+        variableDecl[index] = -1;
+        resultExpr = decl.getRightValue();
     }
 
     @Override
@@ -157,6 +166,7 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
 
     @Override
     public void visit(InvocationExpr expr) {
+        hasMethodCall = true;
         Expr[] args = new Expr[expr.getArguments().size()];
         for (int i = expr.getArguments().size() - 1; i >= 0; --i) {
             expr.getArguments().get(i).acceptVisitor(this);
@@ -266,6 +276,9 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
             if (!(statement.getLeftValue() instanceof VariableExpr)) {
                 statement.getLeftValue().acceptVisitor(this);
                 left = resultExpr;
+            } else {
+                VariableExpr var = (VariableExpr)statement.getLeftValue();
+                variableDecl[var.getIndex()] = resultSequence.size();
             }
             statement.setLeftValue(left);
             statement.setRightValue(right);
@@ -273,34 +286,57 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
         }
     }
 
-    private List<Statement> processSequence(List<Statement> statements, boolean strict) {
+    private List<Statement> processSequence(List<Statement> statements) {
+        boolean hasMethodCallBackup = hasMethodCall;
         List<Statement> backup = resultSequence;
+        int[] variableDeclBackup = variableDecl;
+        List<Boolean> invocationsBackup = invocations;
+        invocations = new ArrayList<>();
+        resultSequence = new ArrayList<>();
+        variableDecl = new int[stats.reads.length];
+        Arrays.fill(variableDecl, -1);
+        processSequenceImpl(statements);
         List<Statement> result = new ArrayList<>();
-        if (strict) {
-            resultSequence = result;
-        }
-        outer: for (int i = 0; i < statements.size(); ++i) {
-            Statement part = statements.get(i);
-            part.acceptVisitor(this);
-            List<Statement> newStatements = new ArrayList<>();
-            if (resultStmt instanceof SequentialStatement) {
-                newStatements.addAll(((SequentialStatement)resultStmt).getSequence());
-            } else {
-                newStatements.add(resultStmt);
-            }
-            for (int j = 0; j < newStatements.size(); ++j) {
-                Statement newStatement = newStatements.get(j);
-                resultSequence = result;
-                result.add(newStatement);
-                if (newStatement instanceof BreakStatement) {
-                    break outer;
-                }
+        for (Statement part : resultSequence) {
+            if (part != null) {
+                result.add(part);
             }
         }
         resultSequence = backup;
+        variableDecl = variableDeclBackup;
+        invocations = invocationsBackup;
+        hasMethodCall = hasMethodCallBackup;
         return result;
     }
 
+    private boolean processSequenceImpl(List<Statement> statements) {
+        for (int i = 0; i < statements.size(); ++i) {
+            Statement part = statements.get(i);
+            if (part instanceof SequentialStatement) {
+                if (!processSequenceImpl(((SequentialStatement)part).getSequence())) {
+                    return false;
+                }
+                continue;
+            }
+            hasMethodCall = false;
+            lastMethodCall = resultSequence.size();
+            part.acceptVisitor(this);
+            invocations.add(hasMethodCall);
+            part = resultStmt;
+            if (part instanceof SequentialStatement) {
+                if (!processSequenceImpl(((SequentialStatement)part).getSequence())) {
+                    return false;
+                }
+                continue;
+            }
+            resultSequence.add(part);
+            if (part instanceof BreakStatement) {
+                return false;
+            }
+        }
+        return true;
+    }
+
     private void eliminateRedundantBreaks(List<Statement> statements, IdentifiedStatement exit) {
         if (statements.isEmpty()) {
             return;
@@ -398,7 +434,7 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
 
     @Override
     public void visit(SequentialStatement statement) {
-        List<Statement> statements = processSequence(statement.getSequence(), false);
+        List<Statement> statements = processSequence(statement.getSequence());
         if (statements.size() == 1) {
             resultStmt = statements.get(0);
         } else {
@@ -412,8 +448,8 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
     public void visit(ConditionalStatement statement) {
         statement.getCondition().acceptVisitor(this);
         statement.setCondition(resultExpr);
-        List<Statement> consequent = processSequence(statement.getConsequent(), true);
-        List<Statement> alternative = processSequence(statement.getAlternative(), true);
+        List<Statement> consequent = processSequence(statement.getConsequent());
+        List<Statement> alternative = processSequence(statement.getAlternative());
         if (consequent.isEmpty()) {
             consequent.addAll(alternative);
             alternative.clear();
@@ -428,6 +464,7 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
         statement.getAlternative().clear();
         statement.getAlternative().addAll(alternative);
         resultStmt = statement;
+        hasMethodCall = true;
     }
 
     @Override
@@ -435,14 +472,15 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
         statement.getValue().acceptVisitor(this);
         statement.setValue(resultExpr);
         for (SwitchClause clause : statement.getClauses()) {
-            List<Statement> newBody = processSequence(clause.getBody(), true);
+            List<Statement> newBody = processSequence(clause.getBody());
             clause.getBody().clear();
             clause.getBody().addAll(newBody);
         }
-        List<Statement> newDefault = processSequence(statement.getDefaultClause(), true);
+        List<Statement> newDefault = processSequence(statement.getDefaultClause());
         statement.getDefaultClause().clear();
         statement.getDefaultClause().addAll(newDefault);
         resultStmt = statement;
+        hasMethodCall = true;
     }
 
     @Override
@@ -454,7 +492,7 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
             statement.getBody().clear();
             statement.getBody().addAll(innerLoop.getBody());
         }
-        List<Statement> statements = processSequence(statement.getBody(), true);
+        List<Statement> statements = processSequence(statement.getBody());
         statement.getBody().clear();
         statement.getBody().addAll(statements);
         if (statement.getCondition() != null) {
@@ -481,11 +519,12 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
             break;
         }
         resultStmt = statement;
+        hasMethodCall = true;
     }
 
     @Override
     public void visit(BlockStatement statement) {
-        List<Statement> statements = processSequence(statement.getBody(), false);
+        List<Statement> statements = processSequence(statement.getBody());
         eliminateRedundantBreaks(statements, statement);
         if (referencedStatements.get(statement).equals(0)) {
             SequentialStatement result = new SequentialStatement();
@@ -505,11 +544,13 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
     @Override
     public void visit(BreakStatement statement) {
         resultStmt = statement;
+        hasMethodCall = true;
     }
 
     @Override
     public void visit(ContinueStatement statement) {
         resultStmt = statement;
+        hasMethodCall = true;
     }
 
     @Override
@@ -519,6 +560,7 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
             statement.setResult(resultExpr);
         }
         resultStmt = statement;
+        hasMethodCall = true;
     }
 
     @Override
@@ -526,6 +568,7 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
         statement.getException().acceptVisitor(this);
         statement.setException(resultExpr);
         resultStmt = statement;
+        hasMethodCall = true;
     }
 
     @Override

teavm-core/src/main/java/org/teavm/javascript/RedundantLabelEliminator.java

@@ -0,0 +1,122 @@
+/*
+ *  Copyright 2014 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.javascript;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import org.teavm.javascript.ast.*;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+class RedundantLabelEliminator implements StatementVisitor {
+    private IdentifiedStatement currentBlock;
+    private Set<IdentifiedStatement> hasRefs = new HashSet<>();
+
+    void visitSequence(List<Statement> statements) {
+        for (Statement statement : statements) {
+            statement.acceptVisitor(this);
+        }
+    }
+
+    @Override
+    public void visit(AssignmentStatement statement) {
+    }
+
+    @Override
+    public void visit(SequentialStatement statement) {
+        visitSequence(statement.getSequence());
+    }
+
+    @Override
+    public void visit(ConditionalStatement statement) {
+        visitSequence(statement.getConsequent());
+        visitSequence(statement.getAlternative());
+    }
+
+    @Override
+    public void visit(SwitchStatement statement) {
+        IdentifiedStatement currentBlockBackup = currentBlock;
+        currentBlock = statement;
+        for (SwitchClause clause : statement.getClauses()) {
+            visitSequence(clause.getBody());
+        }
+        visitSequence(statement.getDefaultClause());
+        if (!hasRefs.contains(currentBlock)) {
+            currentBlock.setId(null);
+        }
+        currentBlock = currentBlockBackup;
+    }
+
+    @Override
+    public void visit(WhileStatement statement) {
+        IdentifiedStatement currentBlockBackup = currentBlock;
+        currentBlock = statement;
+        visitSequence(statement.getBody());
+        if (!hasRefs.contains(currentBlock)) {
+            currentBlock.setId(null);
+        }
+        currentBlock = currentBlockBackup;
+    }
+
+    @Override
+    public void visit(BlockStatement statement) {
+        IdentifiedStatement currentBlockBackup = currentBlock;
+        currentBlock = null;
+        visitSequence(statement.getBody());
+        currentBlock = currentBlockBackup;
+    }
+
+    @Override
+    public void visit(ForStatement statement) {
+    }
+
+    @Override
+    public void visit(BreakStatement statement) {
+        if (statement.getTarget() == currentBlock) {
+            statement.setTarget(null);
+        } else {
+            hasRefs.add(statement.getTarget());
+        }
+    }
+
+    @Override
+    public void visit(ContinueStatement statement) {
+        if (statement.getTarget() == currentBlock) {
+            statement.setTarget(null);
+        } else {
+            hasRefs.add(statement.getTarget());
+        }
+    }
+
+    @Override
+    public void visit(ReturnStatement statement) {
+    }
+
+    @Override
+    public void visit(ThrowStatement statement) {
+    }
+
+    @Override
+    public void visit(IncrementStatement statement) {
+    }
+
+    @Override
+    public void visit(InitClassStatement statement) {
+    }
+}

teavm-core/src/main/java/org/teavm/javascript/Renderer.java

@@ -150,11 +150,13 @@ public class Renderer implements ExprVisitor, StatementVisitor {
                         .append(constantToString(value)).append(";").softNewLine();
             }
 
-            writer.appendClass(cls.getName()).append(".prototype").ws().append("=").ws().append("new ")
-                    .append(cls.getParentName() != null ? naming.getNameFor(cls.getParentName()) :
-                    "Object").append("();").softNewLine();
-            writer.appendClass(cls.getName()).append(".prototype.constructor").ws().append("=").ws()
-                    .appendClass(cls.getName()).append(';').softNewLine();
+            if (!cls.getModifiers().contains(NodeModifier.INTERFACE)) {
+                writer.appendClass(cls.getName()).append(".prototype").ws().append("=").ws().append("new ")
+                        .append(cls.getParentName() != null ? naming.getNameFor(cls.getParentName()) :
+                        "Object").append("();").softNewLine();
+                writer.appendClass(cls.getName()).append(".prototype.constructor").ws().append("=").ws()
+                        .appendClass(cls.getName()).append(';').softNewLine();
+            }
             writer.appendClass(cls.getName()).append(".$meta").ws().append("=").ws().append("{").ws();
             writer.append("name").ws().append(":").ws().append("\"").append(cls.getName()).append("\",").ws();
             writer.append("primitive").ws().append(":").ws().append("false,").ws();
@@ -173,37 +175,39 @@ public class Renderer implements ExprVisitor, StatementVisitor {
             }
             writer.append("]");
             writer.ws().append("};").softNewLine();
-            writer.appendClass(cls.getName()).append("_$clinit").ws().append("=").ws().append("function()").ws()
-                    .append("{").softNewLine().indent();
-            writer.appendClass(cls.getName()).append("_$clinit").ws().append("=").ws()
-                    .append("function(){};").newLine();
-            List<String> stubNames = new ArrayList<>();
-            for (MethodNode method : cls.getMethods()) {
-                renderBody(method);
-                stubNames.add(naming.getFullNameFor(method.getReference()));
-            }
-            MethodHolder methodHolder = classSource.getClassHolder(cls.getName()).getMethod(
-                    new MethodDescriptor("<clinit>", ValueType.VOID));
-            if (methodHolder != null) {
-                writer.appendMethodBody(new MethodReference(cls.getName(), methodHolder.getDescriptor()))
-                        .append("();").softNewLine();
-            }
-            writer.outdent().append("}").newLine();
-            for (MethodNode method : cls.getMethods()) {
-                if (!method.getModifiers().contains(NodeModifier.STATIC)) {
-                    renderDeclaration(method);
+            if (!cls.getModifiers().contains(NodeModifier.INTERFACE)) {
+                writer.appendClass(cls.getName()).append("_$clinit").ws().append("=").ws().append("function()").ws()
+                        .append("{").softNewLine().indent();
+                writer.appendClass(cls.getName()).append("_$clinit").ws().append("=").ws()
+                        .append("function(){};").newLine();
+                List<String> stubNames = new ArrayList<>();
+                for (MethodNode method : cls.getMethods()) {
+                    renderBody(method);
+                    stubNames.add(naming.getFullNameFor(method.getReference()));
                 }
-            }
-            if (stubNames.size() > 0) {
-                writer.append("$rt_methodStubs(").appendClass(cls.getName()).append("_$clinit")
-                        .append(",").ws().append("[");
-                for (int i = 0; i < stubNames.size(); ++i) {
-                    if (i > 0) {
-                        writer.append(",").ws();
+                MethodHolder methodHolder = classSource.getClassHolder(cls.getName()).getMethod(
+                        new MethodDescriptor("<clinit>", ValueType.VOID));
+                if (methodHolder != null) {
+                    writer.appendMethodBody(new MethodReference(cls.getName(), methodHolder.getDescriptor()))
+                            .append("();").softNewLine();
+                }
+                writer.outdent().append("}").newLine();
+                for (MethodNode method : cls.getMethods()) {
+                    if (!method.getModifiers().contains(NodeModifier.STATIC)) {
+                        renderDeclaration(method);
                     }
-                    writer.append("'").append(stubNames.get(i)).append("'");
                 }
-                writer.append("]);").newLine();
+                if (stubNames.size() > 0) {
+                    writer.append("$rt_methodStubs(").appendClass(cls.getName()).append("_$clinit")
+                            .append(",").ws().append("[");
+                    for (int i = 0; i < stubNames.size(); ++i) {
+                        if (i > 0) {
+                            writer.append(",").ws();
+                        }
+                        writer.append("'").append(stubNames.get(i)).append("'");
+                    }
+                    writer.append("]);").newLine();
+                }
             }
         } catch (NamingException e) {
             throw new RenderingException("Error rendering class " + cls.getName() + ". See a cause for details", e);
@@ -489,7 +493,11 @@ public class Renderer implements ExprVisitor, StatementVisitor {
     @Override
     public void visit(BreakStatement statement) {
         try {
-            writer.append("break ").append(statement.getTarget().getId()).append(";").softNewLine();
+            writer.append("break");
+            if (statement.getTarget() != null) {
+                writer.append(' ').append(statement.getTarget().getId());
+            }
+            writer.append(";").softNewLine();
         } catch (IOException e) {
             throw new RenderingException("IO error occured", e);
         }
@@ -498,7 +506,11 @@ public class Renderer implements ExprVisitor, StatementVisitor {
     @Override
     public void visit(ContinueStatement statement) {
         try {
-            writer.append("continue ").append(statement.getTarget().getId()).append(";").softNewLine();
+            writer.append("continue");
+            if (statement.getTarget() != null) {
+                writer.append(' ').append(statement.getTarget().getId());
+            }
+            writer.append(";").softNewLine();
         } catch (IOException e) {
             throw new RenderingException("IO error occured", e);
         }

teavm-core/src/main/java/org/teavm/javascript/ast/ClassNode.java

@@ -16,7 +16,9 @@
 package org.teavm.javascript.ast;
 
 import java.util.ArrayList;
+import java.util.EnumSet;
 import java.util.List;
+import java.util.Set;
 
 /**
  *
@@ -25,6 +27,7 @@ import java.util.List;
 public class ClassNode {
     private String name;
     private String parentName;
+    private Set<NodeModifier> modifiers = EnumSet.noneOf(NodeModifier.class);
     private List<FieldNode> fields = new ArrayList<>();
     private List<MethodNode> methods = new ArrayList<>();
     private List<String> interfaces = new ArrayList<>();
@@ -53,4 +56,8 @@ public class ClassNode {
     public List<String> getInterfaces() {
         return interfaces;
     }
+
+    public Set<NodeModifier> getModifiers() {
+        return modifiers;
+    }
 }

teavm-core/src/main/java/org/teavm/javascript/ast/NodeModifier.java

@@ -20,5 +20,6 @@ package org.teavm.javascript.ast;
  * @author Alexey Andreev <konsoletyper@gmail.com>
  */
 public enum NodeModifier {
-    STATIC
+    STATIC,
+    INTERFACE
 }