Don't generate redundant clinit instructions

core/src/main/java/org/teavm/backend/wasm/WasmTarget.java

@@ -316,7 +316,7 @@ public class WasmTarget implements TeaVMTarget {
 
     private void emitC(WasmModule module, BuildTarget buildTarget, String outputName) throws IOException {
         WasmCRenderer renderer = new WasmCRenderer();
-        renderer.setLineNumbersEmitted(debugging);
+        //renderer.setLineNumbersEmitted(debugging);
         renderer.render(module);
         try (OutputStream output = buildTarget.createResource(outputName);
                 Writer writer = new OutputStreamWriter(output, "UTF-8")) {

core/src/main/java/org/teavm/backend/wasm/generate/WasmGenerator.java

@@ -30,6 +30,7 @@ import org.teavm.model.MethodReference;
 import org.teavm.model.Program;
 import org.teavm.model.ValueType;
 import org.teavm.model.instructions.InitClassInstruction;
+import org.teavm.model.lowlevel.ClassInitializerEliminator;
 import org.teavm.model.lowlevel.ClassInitializerTransformer;
 
 public class WasmGenerator {
@@ -58,6 +59,7 @@ public class WasmGenerator {
             entryBlock.getInstructions().add(0, initInsn);
         }
 
+        new ClassInitializerEliminator(classSource).apply(program);
         new ClassInitializerTransformer().transform(program);
 
         RegularMethodNode methodAst = decompiler.decompileRegular(bodyMethod);

core/src/main/java/org/teavm/model/lowlevel/ClassInitializerEliminator.java

@@ -0,0 +1,91 @@
+/*
+ *  Copyright 2016 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.model.lowlevel;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import org.teavm.interop.StaticInit;
+import org.teavm.interop.Structure;
+import org.teavm.model.BasicBlock;
+import org.teavm.model.ClassReader;
+import org.teavm.model.ClassReaderSource;
+import org.teavm.model.Instruction;
+import org.teavm.model.MethodDescriptor;
+import org.teavm.model.Program;
+import org.teavm.model.instructions.EmptyInstruction;
+import org.teavm.model.instructions.InitClassInstruction;
+
+public class ClassInitializerEliminator {
+    private ClassReaderSource unprocessedClassSource;
+    private Map<String, Boolean> cache = new HashMap<>();
+
+    public ClassInitializerEliminator(ClassReaderSource unprocessedClassSource) {
+        this.unprocessedClassSource = unprocessedClassSource;
+    }
+
+    public void apply(Program program) {
+        for (int i = 0; i < program.basicBlockCount(); ++i) {
+            BasicBlock block = program.basicBlockAt(i);
+            List<Instruction> instructions = block.getInstructions();
+            for (int j = 0; j < instructions.size(); ++j) {
+                Instruction insn = instructions.get(j);
+                if (insn instanceof InitClassInstruction) {
+                    if (!filter(((InitClassInstruction) insn).getClassName())) {
+                        EmptyInstruction empty = new EmptyInstruction();
+                        empty.setLocation(insn.getLocation());
+                        instructions.set(j, empty);
+                    }
+                }
+            }
+        }
+    }
+
+    private boolean filter(String className) {
+        return cache.computeIfAbsent(className, key -> clinitNeeded(key) && !isStaticInit(key) && !isStructure(key));
+    }
+
+    private boolean clinitNeeded(String className) {
+        ClassReader cls = unprocessedClassSource.get(className);
+        if (cls == null) {
+            return true;
+        }
+
+        return cls.getMethod(new MethodDescriptor("<clinit>", void.class)) != null;
+    }
+
+    private boolean isStaticInit(String className) {
+        ClassReader cls = unprocessedClassSource.get(className);
+        if (cls == null) {
+            return false;
+        }
+        return cls.getAnnotations().get(StaticInit.class.getName()) != null;
+    }
+
+    private boolean isStructure(String className) {
+        while (!className.equals(Structure.class.getName())) {
+            ClassReader cls = unprocessedClassSource.get(className);
+            if (cls == null) {
+                return false;
+            }
+            if (cls.getParent() == null || cls.getName().equals(cls.getParent())) {
+                return false;
+            }
+            className = cls.getParent();
+        }
+        return true;
+    }
+}

interop/core/src/main/java/org/teavm/interop/Address.java

@@ -15,6 +15,7 @@
  */
 package org.teavm.interop;
 
+@StaticInit
 public final class Address {
     public native Address add(int offset);