Add inlining of JSBody scripts

teavm-jso-impl/src/main/java/org/teavm/jso/plugin/JSBodyAstEmitter.java

@@ -16,7 +16,7 @@
 package org.teavm.jso.plugin;
 
 import java.io.IOException;
-import org.mozilla.javascript.ast.AstRoot;
+import org.mozilla.javascript.ast.AstNode;
 import org.teavm.codegen.SourceWriter;
 import org.teavm.javascript.spi.GeneratorContext;
 import org.teavm.javascript.spi.InjectorContext;
@@ -28,10 +28,10 @@ import org.teavm.model.MethodReference;
  */
 class JSBodyAstEmitter implements JSBodyEmitter {
     private boolean isStatic;
-    private AstRoot ast;
+    private AstNode ast;
     private String[] parameterNames;
 
-    public JSBodyAstEmitter(boolean isStatic, AstRoot ast, String[] parameterNames) {
+    public JSBodyAstEmitter(boolean isStatic, AstNode ast, String[] parameterNames) {
         this.isStatic = isStatic;
         this.ast = ast;
         this.parameterNames = parameterNames;
@@ -51,7 +51,6 @@ class JSBodyAstEmitter implements JSBodyEmitter {
         }
         astWriter.hoist(ast);
         astWriter.print(ast);
-        context.getWriter().softNewLine();
     }
 
     @Override

teavm-jso-impl/src/main/java/org/teavm/jso/plugin/JSBodyInlineUtil.java

@@ -0,0 +1,125 @@
+/*
+ *  Copyright 2015 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.jso.plugin;
+
+import java.util.HashMap;
+import java.util.Map;
+import org.mozilla.javascript.Token;
+import org.mozilla.javascript.ast.AstNode;
+import org.mozilla.javascript.ast.AstRoot;
+import org.mozilla.javascript.ast.ExpressionStatement;
+import org.mozilla.javascript.ast.Name;
+import org.mozilla.javascript.ast.NodeVisitor;
+import org.mozilla.javascript.ast.ReturnStatement;
+import org.mozilla.javascript.ast.ThrowStatement;
+import org.teavm.model.MethodReference;
+import org.teavm.model.ValueType;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+final class JSBodyInlineUtil {
+    private static final int COMPLEXITY_THRESHOLD = 20;
+    private JSBodyInlineUtil() {
+    }
+
+    public static AstNode isSuitableForInlining(MethodReference method, String[] parameters, AstRoot ast) {
+        AstNode statement = isSingleStatement(ast);
+        if (statement == null) {
+            return null;
+        }
+        AstNode expression = getExpression(method, statement);
+        if (expression == null) {
+            return null;
+        }
+
+        ComplexityCounter complexityCounter = new ComplexityCounter();
+        expression.visit(complexityCounter);
+        if (complexityCounter.getComplexity() > COMPLEXITY_THRESHOLD) {
+            return null;
+        }
+
+        VariableUsageCounter usageCounter = new VariableUsageCounter();
+        expression.visit(usageCounter);
+        for (String param : parameters) {
+            if (usageCounter.getUsage(param) > 1) {
+                return null;
+            }
+        }
+
+        return expression;
+    }
+
+    private static AstNode getExpression(MethodReference method, AstNode statement) {
+        if (method.getReturnType() == ValueType.VOID) {
+            if (statement instanceof ExpressionStatement) {
+                return ((ExpressionStatement) statement).getExpression();
+            } else if (statement instanceof ThrowStatement) {
+                return ((ThrowStatement) statement).getExpression();
+            }
+        } else {
+            if (statement instanceof ReturnStatement) {
+                return ((ReturnStatement) statement).getReturnValue();
+            }
+        }
+        return null;
+    }
+
+    private static AstNode isSingleStatement(AstNode ast) {
+        if (ast.getFirstChild() == null || ast.getFirstChild().getNext() != null) {
+            return null;
+        }
+        if (ast.getFirstChild().getType() == Token.BLOCK) {
+            return isSingleStatement((AstNode) ast.getFirstChild());
+        }
+        return (AstNode) ast.getFirstChild();
+    }
+
+    static class ComplexityCounter implements NodeVisitor {
+        private int complexity;
+
+        public int getComplexity() {
+            return complexity;
+        }
+
+        @Override
+        public boolean visit(AstNode node) {
+            ++complexity;
+            return true;
+        }
+    }
+
+    static class VariableUsageCounter implements NodeVisitor {
+        private Map<String, Integer> usages = new HashMap<>();
+
+        public int getUsage(String varName) {
+            return usages.computeIfAbsent(varName, i -> 0);
+        }
+
+        @Override
+        public boolean visit(AstNode node) {
+            if (node instanceof Name) {
+                Name name = (Name) node;
+                if (!name.isLocalName()) {
+                    String id = name.getIdentifier();
+                    usages.put(id, getUsage(id));
+                }
+            }
+            return true;
+        }
+    }
+}

teavm-jso-impl/src/main/java/org/teavm/jso/plugin/JSBodyRepository.java

@@ -29,4 +29,5 @@ class JSBodyRepository {
     public final Map<MethodReference, JSBodyEmitter> emitters = new HashMap<>();
     public final Map<MethodReference, MethodReference> methodMap = new HashMap<>();
     public final Set<MethodReference> processedMethods = new HashSet<>();
+    public final Set<MethodReference> inlineMethods = new HashSet<>();
 }

teavm-jso-impl/src/main/java/org/teavm/jso/plugin/JavascriptNativeProcessor.java

@@ -27,9 +27,11 @@ import java.util.Set;
 import java.util.function.Function;
 import org.mozilla.javascript.CompilerEnvirons;
 import org.mozilla.javascript.Context;
+import org.mozilla.javascript.ast.AstNode;
 import org.mozilla.javascript.ast.AstRoot;
 import org.teavm.diagnostics.Diagnostics;
 import org.teavm.javascript.spi.GeneratedBy;
+import org.teavm.javascript.spi.InjectedBy;
 import org.teavm.javascript.spi.Sync;
 import org.teavm.jso.JSBody;
 import org.teavm.jso.JSFunctor;
@@ -570,8 +572,14 @@ class JavascriptNativeProcessor {
             repository.emitters.put(proxyMethod, new JSBodyBloatedEmitter(isStatic, proxyMethod,
                     script, parameterNames));
         } else {
-            repository.emitters.put(proxyMethod, new JSBodyAstEmitter(isStatic, rootNode,
-                    parameterNames));
+            AstNode expr = JSBodyInlineUtil.isSuitableForInlining(methodToProcess.getReference(),
+                    parameterNames, rootNode);
+            if (expr != null) {
+                repository.inlineMethods.add(methodToProcess.getReference());
+            } else {
+                expr = rootNode;
+            }
+            repository.emitters.put(proxyMethod, new JSBodyAstEmitter(isStatic, expr, parameterNames));
         }
         repository.methodMap.put(methodToProcess.getReference(), proxyMethod);
     }
@@ -586,7 +594,9 @@ class JavascriptNativeProcessor {
                     MethodHolder proxyMethod = new MethodHolder(proxyRef.getDescriptor());
                     proxyMethod.getModifiers().add(ElementModifier.NATIVE);
                     proxyMethod.getModifiers().add(ElementModifier.STATIC);
-                    AnnotationHolder generatorAnnot = new AnnotationHolder(GeneratedBy.class.getName());
+                    boolean inline = repository.inlineMethods.contains(methodRef);
+                    AnnotationHolder generatorAnnot = new AnnotationHolder(inline
+                            ? InjectedBy.class.getName() : GeneratedBy.class.getName());
                     generatorAnnot.getValues().put("value",
                             new AnnotationValue(ValueType.parse(JSBodyGenerator.class)));
                     proxyMethod.getAnnotations().add(generatorAnnot);