write the vtable of objects to the data section. Use the vtable offset into the data section in the new operation of objects.

src/de/inetsoftware/jwebassembly/binary/BinaryModuleWriter.java

@@ -31,6 +31,7 @@ import javax.annotation.Nullable;
 import de.inetsoftware.jwebassembly.JWebAssembly;
 import de.inetsoftware.jwebassembly.module.FunctionName;
 import de.inetsoftware.jwebassembly.module.ModuleWriter;
+import de.inetsoftware.jwebassembly.module.TypeManager.StructType;
 import de.inetsoftware.jwebassembly.module.ValueTypeConvertion;
 import de.inetsoftware.jwebassembly.module.WasmTarget;
 import de.inetsoftware.jwebassembly.sourcemap.SourceMapWriter;
@@ -442,9 +443,19 @@ public class BinaryModuleWriter extends ModuleWriter implements InstructionOpcod
      * {@inheritDoc}
      */
     @Override
-    protected int writeStruct( String typeName, List<NamedStorageType> fields ) throws IOException {
+    protected int writeStructType( StructType type ) throws IOException {
+        type.setVTable( dataStream.size() );
+        for( FunctionName funcName : type.getMethods() ) {
+            int functIdx = getFunction( funcName ).id;
+            // little-endian byte order
+            dataStream.write( functIdx >>> 0 );
+            dataStream.write( functIdx >>> 8 );
+            dataStream.write( functIdx >>> 16 );
+            dataStream.write( functIdx >>> 24 );
+        }
+
         int typeId = functionTypes.size();
-        functionTypes.add( new StructTypeEntry( fields ) );
+        functionTypes.add( new StructTypeEntry( type.getFields() ) );
         return typeId;
     }
 

src/de/inetsoftware/jwebassembly/module/ModuleGenerator.java

@@ -443,9 +443,14 @@ public class ModuleGenerator {
                     case Struct:
                         WasmStructInstruction instr = (WasmStructInstruction)instruction;
                         if( instr.getOperator() == StructOperator.NEW_DEFAULT ) {
-                            List<NamedStorageType> list = instr.getStructType().getFields();
+                            StructType structType = instr.getStructType();
+                            List<NamedStorageType> list = structType.getFields();
                             for( NamedStorageType storageType : list ) {
-                                writer.writeDefaultValue( storageType.getType() );
+                                if( TypeManager.VTABLE == storageType.getName() ) {
+                                    writer.writeConst( structType.getVTable(), ValueType.i32 );
+                                } else {
+                                    writer.writeDefaultValue( storageType.getType() );
+                                }
                             }
                         }
                         break;

src/de/inetsoftware/jwebassembly/module/ModuleWriter.java

@@ -17,11 +17,11 @@ package de.inetsoftware.jwebassembly.module;
 
 import java.io.Closeable;
 import java.io.IOException;
-import java.util.List;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
+import de.inetsoftware.jwebassembly.module.TypeManager.StructType;
 import de.inetsoftware.jwebassembly.wasm.AnyType;
 import de.inetsoftware.jwebassembly.wasm.ArrayOperator;
 import de.inetsoftware.jwebassembly.wasm.NamedStorageType;
@@ -47,15 +47,13 @@ public abstract class ModuleWriter implements Closeable {
     /**
      * Write a type/struct.
      * 
-     * @param typeName
+     * @param type
-     *            the name
+     *            the type to declare/write
-     * @param fields
-     *            the fields
      * @return type ID
      * @throws IOException
      *             if any I/O error occur
      */
-    protected abstract int writeStruct( String typeName, List<NamedStorageType> fields ) throws IOException;
+    protected abstract int writeStructType( StructType type ) throws IOException;
 
     /**
      * Mark to write exceptions

src/de/inetsoftware/jwebassembly/module/TypeManager.java

@@ -42,8 +42,9 @@ import de.inetsoftware.jwebassembly.wasm.ValueType;
  */
 public class TypeManager {
 
-    private Map<String, StructType> map = new LinkedHashMap<>();
+    static final String             VTABLE = ".vtable";
 
+    private Map<String, StructType> map    = new LinkedHashMap<>();
 
     /**
      * Finish the prepare and write the types. Now no new types and functions should be added.
@@ -110,7 +111,7 @@ public class TypeManager {
      * 
      * @author Volker Berlin
      */
-    static class StructType implements AnyType {
+    public static class StructType implements AnyType {
 
         private final String           name;
 
@@ -118,7 +119,12 @@ public class TypeManager {
 
         private List<NamedStorageType> fields;
 
-        private List<String>           methods;
+        private List<FunctionName>     methods;
+
+        /**
+         * The offset to the vtable in the data section.
+         */
+        private int                    vtableOffset;
 
         /**
          * Create a reference to type
@@ -148,7 +154,7 @@ public class TypeManager {
             fields = new ArrayList<>();
             methods = new ArrayList<>();
             listStructFields( name, functions, types, libraries );
-            code = writer.writeStruct( name, fields );
+            code = writer.writeStructType( this );
         }
 
         /**
@@ -176,7 +182,7 @@ public class TypeManager {
                 String superClassName = superClass.getName();
                 listStructFields( superClassName, functions, types, libraries );
             } else {
-                fields.add( new NamedStorageType( ValueType.i32, className, ".vtable" ) );
+                fields.add( new NamedStorageType( ValueType.i32, className, VTABLE ) );
             }
 
             for( FieldInfo field : classFile.getFields() ) {
@@ -187,16 +193,23 @@ public class TypeManager {
             }
 
             for( MethodInfo method : classFile.getMethods() ) {
-                if( method.isStatic() ) {
+                if( method.isStatic() || "<init>".equals( method.getName() ) ) {
                     continue;
                 }
                 FunctionName funcName = new FunctionName( method );
                 if( functions.needToWrite( funcName ) ) {
-                    String signature = funcName.methodName + funcName.signature;
+                    int idx = 0;
-                    int idx = methods.indexOf( signature );
+                    // search if the method is already in our list
-                    if( idx < 0 ) {
+                    for( ; idx < methods.size(); idx++ ) {
-                        idx = methods.size();
+                        FunctionName func = methods.get( idx );
-                        methods.add( signature );
+                        if( func.methodName.equals( funcName.methodName ) && func.signature.equals( funcName.signature ) ) {
+                            methods.set( idx, funcName ); // use the override method
+                            break;
+                        }
+                    }
+                    if( idx == methods.size() ) {
+                        // if a new method
+                        methods.add( funcName );
                     }
                     functions.setFunctionIndex( funcName, idx );
                 }
@@ -227,6 +240,34 @@ public class TypeManager {
             return fields;
         }
 
+        /**
+         * Get the virtual function/methods
+         * 
+         * @return the methods
+         */
+        public List<FunctionName> getMethods() {
+            return methods;
+        }
+
+        /**
+         * Set the offset of the vtable in the data section
+         * 
+         * @param vtableOffset
+         *            the offset
+         */
+        public void setVTable( int vtableOffset ) {
+            this.vtableOffset = vtableOffset;
+        }
+
+        /**
+         * Get the vtable offset.
+         * 
+         * @return the offset
+         */
+        public int getVTable() {
+            return this.vtableOffset;
+        }
+
         /**
          * {@inheritDoc}
          */

src/de/inetsoftware/jwebassembly/text/TextModuleWriter.java

@@ -21,7 +21,6 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
-import java.util.List;
 import java.util.Map;
 
 import javax.annotation.Nonnull;
@@ -31,6 +30,7 @@ import de.inetsoftware.jwebassembly.JWebAssembly;
 import de.inetsoftware.jwebassembly.WasmException;
 import de.inetsoftware.jwebassembly.module.FunctionName;
 import de.inetsoftware.jwebassembly.module.ModuleWriter;
+import de.inetsoftware.jwebassembly.module.TypeManager.StructType;
 import de.inetsoftware.jwebassembly.module.ValueTypeConvertion;
 import de.inetsoftware.jwebassembly.wasm.AnyType;
 import de.inetsoftware.jwebassembly.wasm.ArrayOperator;
@@ -148,14 +148,24 @@ public class TextModuleWriter extends ModuleWriter {
      * {@inheritDoc}
      */
     @Override
-    protected int writeStruct( String typeName, List<NamedStorageType> fields ) throws IOException {
+    protected int writeStructType( StructType type ) throws IOException {
+        type.setVTable( dataStream.size() );
+        for( FunctionName funcName : type.getMethods() ) {
+            int functIdx = functions.get( funcName.signatureName );
+            // little-endian byte order
+            dataStream.write( functIdx >>> 0 );
+            dataStream.write( functIdx >>> 8 );
+            dataStream.write( functIdx >>> 16 );
+            dataStream.write( functIdx >>> 24 );
+        }
+
         int oldInset = inset;
         inset = 1;
         newline( output );
-        typeName = normalizeName( typeName );
+        String typeName = normalizeName( type.getName() );
         output.append( "(type $" ).append( typeName ).append( " (struct" );
         inset++;
-        for( NamedStorageType field : fields ) {
+        for( NamedStorageType field : type.getFields() ) {
             newline( output );
             output.append( "(field" );
             if( debugNames && field.getName() != null ) {