Minor optimizations

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

@@ -15,16 +15,33 @@
  */
 package org.teavm.javascript;
 
-import java.util.HashMap;
+import java.util.List;
-import java.util.Map;
 import org.teavm.javascript.ast.*;
 
 /**
  *
  * @author Alexey Andreev
  */
-class BlockRefCountVisitor implements StatementVisitor {
+class CertainBlockCountVisitor implements StatementVisitor {
-    Map<IdentifiedStatement, Integer> refs = new HashMap<>();
+    private BlockStatement blockToCount;
+    private int count;
+
+    public CertainBlockCountVisitor(BlockStatement blockToCount) {
+        this.blockToCount = blockToCount;
+    }
+
+    public int getCount() {
+        return count;
+    }
+
+    public void visit(List<Statement> statements) {
+        if (statements == null) {
+            return;
+        }
+        for (Statement part : statements) {
+            part.acceptVisitor(this);
+        }
+    }
 
     @Override
     public void visit(AssignmentStatement statement) {
@@ -32,48 +49,31 @@ class BlockRefCountVisitor implements StatementVisitor {
 
     @Override
     public void visit(SequentialStatement statement) {
-        for (Statement part : statement.getSequence()) {
+        visit(statement.getSequence());
-            part.acceptVisitor(this);
-        }
     }
 
     @Override
     public void visit(ConditionalStatement statement) {
-        for (Statement stmt : statement.getConsequent()) {
+        visit(statement.getConsequent());
-            stmt.acceptVisitor(this);
+        visit(statement.getAlternative());
-        }
-        for (Statement stmt : statement.getAlternative()) {
-            stmt.acceptVisitor(this);
-        }
     }
 
     @Override
     public void visit(SwitchStatement statement) {
-        refs.put(statement, 0);
         for (SwitchClause clause : statement.getClauses()) {
-            for (Statement part : clause.getBody()) {
+            visit(clause.getBody());
-                part.acceptVisitor(this);
-            }
-        }
-        for (Statement part : statement.getDefaultClause()) {
-            part.acceptVisitor(this);
         }
+        visit(statement.getDefaultClause());
     }
 
     @Override
     public void visit(WhileStatement statement) {
-        refs.put(statement, 0);
+        visit(statement.getBody());
-        for (Statement part : statement.getBody()) {
-            part.acceptVisitor(this);
-        }
     }
 
     @Override
     public void visit(BlockStatement statement) {
-        refs.put(statement, 0);
+        visit(statement.getBody());
-        for (Statement part : statement.getBody()) {
-            part.acceptVisitor(this);
-        }
     }
 
     @Override
@@ -82,12 +82,16 @@ class BlockRefCountVisitor implements StatementVisitor {
 
     @Override
     public void visit(BreakStatement statement) {
-        refs.put(statement.getTarget(), refs.get(statement.getTarget()) + 1);
+        if (statement.getTarget() == blockToCount) {
+            ++count;
+        }
     }
 
     @Override
     public void visit(ContinueStatement statement) {
-        refs.put(statement.getTarget(), refs.get(statement.getTarget()) + 1);
+        if (statement.getTarget() == blockToCount) {
+            ++count;
+        }
     }
 
     @Override
@@ -108,11 +112,7 @@ class BlockRefCountVisitor implements StatementVisitor {
 
     @Override
     public void visit(TryCatchStatement statement) {
-        for (Statement part : statement.getProtectedBody()) {
+        visit(statement.getProtectedBody());
-            part.acceptVisitor(this);
+        visit(statement.getHandler());
-        }
-        for (Statement part : statement.getHandler()) {
-            part.acceptVisitor(this);
-        }
     }
 }

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

@@ -27,10 +27,7 @@ public class Optimizer {
     public void optimize(RegularMethodNode method, Program program) {
         ReadWriteStatsBuilder stats = new ReadWriteStatsBuilder(method.getVariables().size());
         stats.analyze(program);
-        BlockRefCountVisitor refsCounter = new BlockRefCountVisitor();
-        method.getBody().acceptVisitor(refsCounter);
         OptimizingVisitor optimizer = new OptimizingVisitor(stats);
-        optimizer.referencedStatements = refsCounter.refs;
         method.getBody().acceptVisitor(optimizer);
         method.setBody(optimizer.resultStmt);
         int paramCount = method.getReference().parameterCount();

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

@@ -26,7 +26,6 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
     public Expr resultExpr;
     public Statement resultStmt;
     private ReadWriteStatsBuilder stats;
-    Map<IdentifiedStatement, Integer> referencedStatements = new HashMap<>();
     private List<Statement> resultSequence;
 
     public OptimizingVisitor(ReadWriteStatsBuilder stats) {
@@ -344,8 +343,6 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
                     if (last instanceof BreakStatement) {
                         BreakStatement breakStmt = (BreakStatement)last;
                         if (exit != null && exit == breakStmt.getTarget()) {
-                            int refs = referencedStatements.get(breakStmt.getTarget());
-                            referencedStatements.put(breakStmt.getTarget(), refs - 1);
                             cond.getConsequent().remove(cond.getConsequent().size() - 1);
                             List<Statement> remaining = statements.subList(i + 1, statements.size());
                             cond.getAlternative().addAll(remaining);
@@ -358,8 +355,6 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
                     if (last instanceof BreakStatement) {
                         BreakStatement breakStmt = (BreakStatement)last;
                         if (exit != null && exit == breakStmt.getTarget()) {
-                            int refs = referencedStatements.get(breakStmt.getTarget());
-                            referencedStatements.put(breakStmt.getTarget(), refs - 1);
                             cond.getAlternative().remove(cond.getConsequent().size() - 1);
                             List<Statement> remaining = statements.subList(i + 1, statements.size());
                             cond.getConsequent().addAll(remaining);
@@ -476,6 +471,15 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
             statement.getBody().addAll(innerLoop.getBody());
         }
         List<Statement> statements = processSequence(statement.getBody());
+        for (int i = 0; i < statements.size(); ++i) {
+            if (statements.get(i) instanceof ContinueStatement) {
+                ContinueStatement continueStmt = (ContinueStatement)statements.get(i);
+                if (continueStmt.getTarget() == statement) {
+                    statements.subList(i, statements.size()).clear();
+                    break;
+                }
+            }
+        }
         statement.getBody().clear();
         statement.getBody().addAll(statements);
         if (statement.getCondition() != null) {
@@ -511,7 +515,9 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
     public void visit(BlockStatement statement) {
         List<Statement> statements = processSequence(statement.getBody());
         eliminateRedundantBreaks(statements, statement);
-        if (referencedStatements.get(statement).equals(0)) {
+        CertainBlockCountVisitor usageCounter = new CertainBlockCountVisitor(statement);
+        usageCounter.visit(statements);
+        if (usageCounter.getCount() == 0) {
             SequentialStatement result = new SequentialStatement();
             result.getSequence().addAll(statements);
             resultStmt = result;

teavm-core/src/main/java/org/teavm/optimization/ArrayUnwrapMotion.java

@@ -0,0 +1,73 @@
+/*
+ *  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.optimization;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.teavm.model.*;
+import org.teavm.model.instructions.EmptyInstruction;
+import org.teavm.model.instructions.UnwrapArrayInstruction;
+import org.teavm.model.util.DefinitionExtractor;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+public class ArrayUnwrapMotion implements MethodOptimization {
+    @Override
+    public void optimize(MethodReader method, Program program) {
+        for (int i = 0; i < program.basicBlockCount(); ++i) {
+            optimize(program.basicBlockAt(i));
+        }
+    }
+
+    private void optimize(BasicBlock block) {
+        List<Instruction> newInstructions = new ArrayList<>();
+        List<Instruction> instructions = block.getInstructions();
+        for (int i = 0; i < instructions.size(); ++i) {
+            Instruction insn = instructions.get(i);
+            if (insn instanceof UnwrapArrayInstruction) {
+                UnwrapArrayInstruction unwrap = (UnwrapArrayInstruction)insn;
+                instructions.set(i, new EmptyInstruction());
+                int def = whereDefined(instructions, i, unwrap.getArray());
+                if (def < 0) {
+                    newInstructions.add(unwrap);
+                } else {
+                    instructions.add(def + 1, unwrap);
+                    ++i;
+                }
+            }
+        }
+        if (!newInstructions.isEmpty()) {
+            instructions.addAll(0, newInstructions);
+        }
+    }
+
+    private int whereDefined(List<Instruction> instructions, int index, Variable var) {
+        DefinitionExtractor def = new DefinitionExtractor();
+        while (index >= 0) {
+            Instruction insn = instructions.get(index);
+            insn.acceptVisitor(def);
+            for (Variable defVar : def.getDefinedVariables()) {
+                if (defVar == var) {
+                    return index;
+                }
+            }
+            --index;
+        }
+        return index;
+    }
+}

teavm-core/src/main/java/org/teavm/optimization/ClassSetOptimizer.java

@@ -36,8 +36,8 @@ public class ClassSetOptimizer {
     }
 
     private List<MethodOptimization> getOptimizations() {
-        return Arrays.<MethodOptimization>asList(new LoopInvariantMotion(), new GlobalValueNumbering(),
+        return Arrays.<MethodOptimization>asList(new ArrayUnwrapMotion(), new LoopInvariantMotion(),
-                new UnusedVariableElimination());
+                new GlobalValueNumbering(), new UnusedVariableElimination());
     }
 
     public void optimizeAll(ListableClassHolderSource classSource) {