diff --git a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/ChromeRDPDebugger.java b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/ChromeRDPDebugger.java
index 38980bd54..d41c827b0 100644
--- a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/ChromeRDPDebugger.java
+++ b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/ChromeRDPDebugger.java
@@ -1,16 +1,16 @@
 package org.teavm.chromerdp;
 
 import java.io.IOException;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.Exchanger;
 import java.util.concurrent.atomic.AtomicInteger;
 import org.codehaus.jackson.JsonNode;
 import org.codehaus.jackson.map.ObjectMapper;
-import org.teavm.chromerdp.data.CallFrameDTO;
-import org.teavm.chromerdp.data.LocationDTO;
-import org.teavm.chromerdp.data.Message;
-import org.teavm.chromerdp.data.Response;
+import org.teavm.chromerdp.data.*;
 import org.teavm.chromerdp.messages.*;
 import org.teavm.debugging.*;
 
@@ -266,6 +266,37 @@ public class ChromeRDPDebugger implements JavaScriptDebugger, ChromeRDPExchangeC
         sendMessage(message);
     }
 
+    List<RDPLocalVariable> getScope(String scopeId) {
+        if (exchange == null) {
+            return Collections.emptyList();
+        }
+        Message message = new Message();
+        message.setId(messageIdGenerator.incrementAndGet());
+        message.setMethod("Runtime.getProperties");
+        GetPropertiesCommand params = new GetPropertiesCommand();
+        params.setObjectId(scopeId);
+        params.setOwnProperties(true);
+        message.setParams(mapper.valueToTree(params));
+        final Exchanger<List<RDPLocalVariable>> exchanger = new Exchanger<>();
+        responseHandlers.put(message.getId(), new ResponseHandler() {
+            @Override public void received(JsonNode node) throws IOException {
+                GetPropertiesResponse response = mapper.reader(GetPropertiesResponse.class).readValue(node);
+                // TODO: parse response
+                try {
+                    exchanger.exchange(new ArrayList<RDPLocalVariable>());
+                } catch (InterruptedException e) {
+                    throw new RuntimeException(e);
+                }
+            }
+        });
+        sendMessage(message);
+        try {
+            return exchanger.exchange(null);
+        } catch (InterruptedException e) {
+            return Collections.emptyList();
+        }
+    }
+
     private <T> T parseJson(Class<T> type, JsonNode node) throws IOException {
         return mapper.reader(type).readValue(node);
     }
@@ -282,7 +313,14 @@ public class ChromeRDPDebugger implements JavaScriptDebugger, ChromeRDPExchangeC
     }
 
     RDPCallFrame map(CallFrameDTO dto) {
-        return new RDPCallFrame(dto.getCallFrameId(), map(dto.getLocation()));
+        String scopeId = null;
+        for (ScopeDTO scope : dto.getScopeChain()) {
+            if (scope.getType().equals("local")) {
+                scopeId = scope.getObject();
+                break;
+            }
+        }
+        return new RDPCallFrame(dto.getCallFrameId(), map(dto.getLocation()), new RDPScope(this, scopeId));
     }
 
     JavaScriptLocation map(LocationDTO dto) {
diff --git a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPCallFrame.java b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPCallFrame.java
index d89ef718d..3ed96bfc6 100644
--- a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPCallFrame.java
+++ b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPCallFrame.java
@@ -15,8 +15,11 @@
  */
 package org.teavm.chromerdp;
 
+import java.util.Collections;
+import java.util.Map;
 import org.teavm.debugging.JavaScriptCallFrame;
 import org.teavm.debugging.JavaScriptLocation;
+import org.teavm.debugging.JavaScriptVariable;
 
 /**
  *
@@ -25,10 +28,13 @@ import org.teavm.debugging.JavaScriptLocation;
 public class RDPCallFrame implements JavaScriptCallFrame {
     private String chromeId;
     private JavaScriptLocation location;
+    private Map<String, JavaScriptVariable> variables;
 
-    public RDPCallFrame(String chromeId, JavaScriptLocation location) {
+    public RDPCallFrame(String chromeId, JavaScriptLocation location,
+            Map<String, ? extends JavaScriptVariable> variables) {
         this.chromeId = chromeId;
         this.location = location;
+        this.variables = Collections.unmodifiableMap(variables);
     }
 
     public String getChromeId() {
@@ -39,4 +45,9 @@ public class RDPCallFrame implements JavaScriptCallFrame {
     public JavaScriptLocation getLocation() {
         return location;
     }
+
+    @Override
+    public Map<String, JavaScriptVariable> getVariables() {
+        return variables;
+    }
 }
diff --git a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPLocalVariable.java b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPLocalVariable.java
new file mode 100644
index 000000000..4bf308ae6
--- /dev/null
+++ b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPLocalVariable.java
@@ -0,0 +1,28 @@
+package org.teavm.chromerdp;
+
+import org.teavm.debugging.JavaScriptValue;
+import org.teavm.debugging.JavaScriptVariable;
+
+/**
+ *
+ * @author Alexey Andreev <konsoletyper@gmail.com>
+ */
+public class RDPLocalVariable implements JavaScriptVariable {
+    private String name;
+    private RDPValue value;
+
+    public RDPLocalVariable(String name, RDPValue value) {
+        this.name = name;
+        this.value = value;
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public JavaScriptValue getValue() {
+        return value;
+    }
+}
diff --git a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPScope.java b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPScope.java
new file mode 100644
index 000000000..e024ffa8e
--- /dev/null
+++ b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPScope.java
@@ -0,0 +1,53 @@
+package org.teavm.chromerdp;
+
+import java.util.AbstractMap;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ *
+ * @author Alexey Andreev <konsoletyper@gmail.com>
+ */
+public class RDPScope extends AbstractMap<String, RDPLocalVariable> {
+    private volatile Map<String, RDPLocalVariable> backingMap;
+    private ChromeRDPDebugger debugger;
+    private String id;
+
+    public RDPScope(ChromeRDPDebugger debugger, String id) {
+        this.debugger = debugger;
+        this.id = id;
+    }
+
+    @Override
+    public Set<Entry<String, RDPLocalVariable>> entrySet() {
+        initBackingMap();
+        return backingMap.entrySet();
+    }
+
+    @Override
+    public int size() {
+        initBackingMap();
+        return backingMap.size();
+    }
+
+    @Override
+    public RDPLocalVariable get(Object key) {
+        initBackingMap();
+        return backingMap.get(key);
+    }
+
+    private void initBackingMap() {
+        if (backingMap != null) {
+            return;
+        }
+        if (id == null) {
+            backingMap = new HashMap<>();
+        }
+        Map<String, RDPLocalVariable> newBackingMap = new HashMap<>();
+        for (RDPLocalVariable variable : debugger.getScope(id)) {
+            newBackingMap.put(variable.getName(), variable);
+        }
+        backingMap = newBackingMap;
+    }
+}
diff --git a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPValue.java b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPValue.java
new file mode 100644
index 000000000..6d1743406
--- /dev/null
+++ b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPValue.java
@@ -0,0 +1,28 @@
+package org.teavm.chromerdp;
+
+import java.util.Collections;
+import java.util.Map;
+import org.teavm.debugging.JavaScriptValue;
+import org.teavm.debugging.JavaScriptVariable;
+
+/**
+ *
+ * @author Alexey Andreev <konsoletyper@gmail.com>
+ */
+public class RDPValue implements JavaScriptValue {
+    private String representation;
+
+    public RDPValue(String representation) {
+        this.representation = representation;
+    }
+
+    @Override
+    public String getRepresentation() {
+        return representation;
+    }
+
+    @Override
+    public Map<String, JavaScriptVariable> getProperties() {
+        return Collections.emptyMap();
+    }
+}
diff --git a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/data/CallFrameDTO.java b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/data/CallFrameDTO.java
index 584a50c99..e32b66191 100644
--- a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/data/CallFrameDTO.java
+++ b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/data/CallFrameDTO.java
@@ -25,6 +25,7 @@ import org.codehaus.jackson.annotate.JsonIgnoreProperties;
 public class CallFrameDTO {
     private String callFrameId;
     private LocationDTO location;
+    private ScopeDTO[] scopeChain;
 
     public String getCallFrameId() {
         return callFrameId;
@@ -41,4 +42,12 @@ public class CallFrameDTO {
     public void setLocation(LocationDTO location) {
         this.location = location;
     }
+
+    public ScopeDTO[] getScopeChain() {
+        return scopeChain;
+    }
+
+    public void setScopeChain(ScopeDTO[] scopeChain) {
+        this.scopeChain = scopeChain;
+    }
 }
diff --git a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/data/PropertyDescriptorDTO.java b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/data/PropertyDescriptorDTO.java
new file mode 100644
index 000000000..af4d81169
--- /dev/null
+++ b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/data/PropertyDescriptorDTO.java
@@ -0,0 +1,29 @@
+package org.teavm.chromerdp.data;
+
+import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+
+/**
+ *
+ * @author Alexey Andreev <konsoletyper@gmail.com>
+ */
+@JsonIgnoreProperties(ignoreUnknown = true)
+public class PropertyDescriptorDTO {
+    private String name;
+    private RemoteObjectDTO value;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public RemoteObjectDTO getValue() {
+        return value;
+    }
+
+    public void setValue(RemoteObjectDTO value) {
+        this.value = value;
+    }
+}
diff --git a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/data/RemoteObjectDTO.java b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/data/RemoteObjectDTO.java
new file mode 100644
index 000000000..7b07c5630
--- /dev/null
+++ b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/data/RemoteObjectDTO.java
@@ -0,0 +1,57 @@
+package org.teavm.chromerdp.data;
+
+import org.codehaus.jackson.JsonNode;
+import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+
+/**
+ *
+ * @author Alexey Andreev <konsoletyper@gmail.com>
+ */
+@JsonIgnoreProperties(ignoreUnknown = true)
+public class RemoteObjectDTO {
+    private String className;
+    private String description;
+    private String objectId;
+    private String type;
+    private JsonNode value;
+
+    public String getClassName() {
+        return className;
+    }
+
+    public void setClassName(String className) {
+        this.className = className;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+
+    public String getObjectId() {
+        return objectId;
+    }
+
+    public void setObjectId(String objectId) {
+        this.objectId = objectId;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+
+    public JsonNode getValue() {
+        return value;
+    }
+
+    public void setValue(JsonNode value) {
+        this.value = value;
+    }
+}
diff --git a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/data/ScopeDTO.java b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/data/ScopeDTO.java
new file mode 100644
index 000000000..fda09c677
--- /dev/null
+++ b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/data/ScopeDTO.java
@@ -0,0 +1,29 @@
+package org.teavm.chromerdp.data;
+
+import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+
+/**
+ *
+ * @author Alexey Andreev <konsoletyper@gmail.com>
+ */
+@JsonIgnoreProperties(ignoreUnknown = true)
+public class ScopeDTO {
+    private String object;
+    private String type;
+
+    public String getObject() {
+        return object;
+    }
+
+    public void setObject(String object) {
+        this.object = object;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+}
diff --git a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/messages/GetPropertiesCommand.java b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/messages/GetPropertiesCommand.java
new file mode 100644
index 000000000..5b7baf27c
--- /dev/null
+++ b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/messages/GetPropertiesCommand.java
@@ -0,0 +1,29 @@
+package org.teavm.chromerdp.messages;
+
+import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+
+/**
+ *
+ * @author Alexey Andreev <konsoletyper@gmail.com>
+ */
+@JsonIgnoreProperties(ignoreUnknown = true)
+public class GetPropertiesCommand {
+    private String objectId;
+    private boolean ownProperties;
+
+    public String getObjectId() {
+        return objectId;
+    }
+
+    public void setObjectId(String objectId) {
+        this.objectId = objectId;
+    }
+
+    public boolean isOwnProperties() {
+        return ownProperties;
+    }
+
+    public void setOwnProperties(boolean ownProperties) {
+        this.ownProperties = ownProperties;
+    }
+}
diff --git a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/messages/GetPropertiesResponse.java b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/messages/GetPropertiesResponse.java
new file mode 100644
index 000000000..509cc4324
--- /dev/null
+++ b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/messages/GetPropertiesResponse.java
@@ -0,0 +1,21 @@
+package org.teavm.chromerdp.messages;
+
+import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+import org.teavm.chromerdp.data.PropertyDescriptorDTO;
+
+/**
+ *
+ * @author Alexey Andreev <konsoletyper@gmail.com>
+ */
+@JsonIgnoreProperties(ignoreUnknown = true)
+public class GetPropertiesResponse {
+    private PropertyDescriptorDTO[] properties;
+
+    public PropertyDescriptorDTO[] getProperties() {
+        return properties;
+    }
+
+    public void setProperties(PropertyDescriptorDTO[] properties) {
+        this.properties = properties;
+    }
+}
diff --git a/teavm-classlib/src/main/java/org/teavm/classlib/impl/JavacSupport.java b/teavm-classlib/src/main/java/org/teavm/classlib/impl/JavacSupport.java
index def1bef59..f2bc94084 100644
--- a/teavm-classlib/src/main/java/org/teavm/classlib/impl/JavacSupport.java
+++ b/teavm-classlib/src/main/java/org/teavm/classlib/impl/JavacSupport.java
@@ -33,8 +33,8 @@ public class JavacSupport implements ClassHolderTransformer {
                     ValueType.object("javax.tools.JavaCompiler")));
             Program program = new Program();
             BasicBlock block = program.createBasicBlock();
-            program.createVariable();
-            Variable var = program.createVariable();
+            program.createVariable(null);
+            Variable var = program.createVariable(null);
             ConstructInstruction construct = new ConstructInstruction();
             construct.setReceiver(var);
             construct.setType("com.sun.tools.javac.api.JavacTool");
diff --git a/teavm-core/src/main/java/org/teavm/debugging/CallFrame.java b/teavm-core/src/main/java/org/teavm/debugging/CallFrame.java
index 20edbe8c4..80a51b764 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/CallFrame.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/CallFrame.java
@@ -15,6 +15,8 @@
  */
 package org.teavm.debugging;
 
+import java.util.Collections;
+import java.util.Map;
 import org.teavm.model.MethodReference;
 
 /**
@@ -24,10 +26,12 @@ import org.teavm.model.MethodReference;
 public class CallFrame {
     private SourceLocation location;
     private MethodReference method;
+    private Map<String, LocalVariable> variables;
 
-    CallFrame(SourceLocation location, MethodReference method) {
+    CallFrame(SourceLocation location, MethodReference method, Map<String, LocalVariable> variables) {
         this.location = location;
         this.method = method;
+        this.variables = Collections.unmodifiableMap(variables);
     }
 
     public SourceLocation getLocation() {
@@ -37,4 +41,8 @@ public class CallFrame {
     public MethodReference getMethod() {
         return method;
     }
+
+    public Map<String, LocalVariable> getVariables() {
+        return variables;
+    }
 }
diff --git a/teavm-core/src/main/java/org/teavm/debugging/DebugInformation.java b/teavm-core/src/main/java/org/teavm/debugging/DebugInformation.java
index 5d9eb681f..3997798c5 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/DebugInformation.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/DebugInformation.java
@@ -35,11 +35,14 @@ public class DebugInformation {
     Map<String, Integer> classNameMap;
     String[] methods;
     Map<String, Integer> methodMap;
+    String[] variableNames;
+    Map<String, Integer> variableNameMap;
     FileDescription[] fileDescriptions;
     Mapping fileMapping;
     Mapping classMapping;
     Mapping methodMapping;
     Mapping lineMapping;
+    Mapping[] variableMappings;
 
     public String[] getCoveredSourceFiles() {
         return fileNames.clone();
@@ -99,6 +102,22 @@ public class DebugInformation {
         return getMethodAt(new GeneratedLocation(line, column));
     }
 
+    public String getVariableMeaningAt(int line, int column, String variable) {
+        return getVariableMeaningAt(new GeneratedLocation(line, column), variable);
+    }
+
+    public String getVariableMeaningAt(GeneratedLocation location, String variable) {
+        Integer varIndex = variableNameMap.get(variable);
+        if (varIndex == null) {
+            return null;
+        }
+        Mapping mapping = variableMappings[varIndex];
+        if (mapping == null) {
+            return null;
+        }
+        return componentByKey(mapping, variableNames, location);
+    }
+
     private <T> T componentByKey(Mapping mapping, T[] values, GeneratedLocation location) {
         int keyIndex = indexByKey(mapping, location);
         int valueIndex = keyIndex >= 0 ? mapping.values[keyIndex] : -1;
@@ -124,6 +143,7 @@ public class DebugInformation {
         fileNameMap = mapArray(fileNames);
         classNameMap = mapArray(classNames);
         methodMap = mapArray(methods);
+        variableNameMap = mapArray(variableNames);
     }
 
     private Map<String, Integer> mapArray(String[] array) {
diff --git a/teavm-core/src/main/java/org/teavm/debugging/DebugInformationBuilder.java b/teavm-core/src/main/java/org/teavm/debugging/DebugInformationBuilder.java
index 2d3350418..c4a8ff96a 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/DebugInformationBuilder.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/DebugInformationBuilder.java
@@ -30,10 +30,12 @@ public class DebugInformationBuilder implements DebugInformationEmitter {
     private MappedList files = new MappedList();
     private MappedList classes = new MappedList();
     private MappedList methods = new MappedList();
+    private MappedList variableNames = new MappedList();
     private Mapping fileMapping = new Mapping();
     private Mapping lineMapping = new Mapping();
     private Mapping classMapping = new Mapping();
     private Mapping methodMapping = new Mapping();
+    private Map<Integer, Mapping> variableMappings = new HashMap<>();
     private MethodDescriptor currentMethod;
     private String currentClass;
     private String currentFileName;
@@ -82,6 +84,18 @@ public class DebugInformationBuilder implements DebugInformationEmitter {
         }
     }
 
+    @Override
+    public void emitVariable(String sourceName, String generatedName) {
+        int sourceIndex = variableNames.index(sourceName);
+        int generatedIndex = variableNames.index(generatedName);
+        Mapping mapping = variableMappings.get(generatedIndex);
+        if (mapping == null) {
+            mapping = new Mapping();
+            variableMappings.put(generatedIndex, mapping);
+        }
+        mapping.add(locationProvider, sourceIndex);
+    }
+
     public DebugInformation getDebugInformation() {
         if (debugInformation == null) {
             debugInformation = new DebugInformation();
@@ -92,11 +106,18 @@ public class DebugInformationBuilder implements DebugInformationEmitter {
             debugInformation.classNameMap = classes.getIndexes();
             debugInformation.methods = methods.getItems();
             debugInformation.methodMap = methods.getIndexes();
+            debugInformation.variableNames = variableNames.getItems();
+            debugInformation.variableNameMap = variableNames.getIndexes();
 
             debugInformation.fileMapping = fileMapping.build();
             debugInformation.lineMapping = lineMapping.build();
             debugInformation.classMapping = classMapping.build();
             debugInformation.methodMapping = methodMapping.build();
+            debugInformation.variableMappings = new DebugInformation.Mapping[variableNames.list.size()];
+            for (int var : variableMappings.keySet()) {
+                Mapping mapping = variableMappings.get(var);
+                debugInformation.variableMappings[var] = mapping.build();
+            }
 
             debugInformation.rebuildFileDescriptions();
         }
diff --git a/teavm-core/src/main/java/org/teavm/debugging/DebugInformationEmitter.java b/teavm-core/src/main/java/org/teavm/debugging/DebugInformationEmitter.java
index b88ad22b0..0e794be15 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/DebugInformationEmitter.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/DebugInformationEmitter.java
@@ -30,4 +30,6 @@ public interface DebugInformationEmitter {
     void emitMethod(MethodDescriptor method);
 
     void emitClass(String className);
+
+    void emitVariable(String sourceName, String generatedName);
 }
\ No newline at end of file
diff --git a/teavm-core/src/main/java/org/teavm/debugging/DebugInformationReader.java b/teavm-core/src/main/java/org/teavm/debugging/DebugInformationReader.java
index 59ecb4d86..d37249026 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/DebugInformationReader.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/DebugInformationReader.java
@@ -36,15 +36,30 @@ class DebugInformationReader {
         debugInfo.fileNames = readStrings();
         debugInfo.classNames = readStrings();
         debugInfo.methods = readStrings();
+        debugInfo.variableNames = readStrings();
         debugInfo.fileMapping = readMapping();
         debugInfo.lineMapping = readMapping();
         debugInfo.classMapping = readMapping();
         debugInfo.methodMapping = readMapping();
+        debugInfo.variableMappings = readVariableMappings(debugInfo.variableNames.length);
         debugInfo.rebuildFileDescriptions();
         debugInfo.rebuildMaps();
         return debugInfo;
     }
 
+    private DebugInformation.Mapping[] readVariableMappings(int count) throws IOException {
+        DebugInformation.Mapping[] mappings = new DebugInformation.Mapping[count];
+        int varCount = readUnsignedNumber();
+        while (varCount-- > 0) {
+            int lastVar = 0;
+            for (int i = 0; i < mappings.length; ++i) {
+                lastVar += readUnsignedNumber();
+                mappings[lastVar] = readMapping();
+            }
+        }
+        return mappings;
+    }
+
     private int processSign(int number) {
         boolean negative = (number & 1) != 0;
         number >>>= 1;
diff --git a/teavm-core/src/main/java/org/teavm/debugging/DebugInformationWriter.java b/teavm-core/src/main/java/org/teavm/debugging/DebugInformationWriter.java
index f50d6ba1f..d1402c39d 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/DebugInformationWriter.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/DebugInformationWriter.java
@@ -34,11 +34,37 @@ class DebugInformationWriter {
         writeStringArray(debugInfo.fileNames);
         writeStringArray(debugInfo.classNames);
         writeStringArray(debugInfo.methods);
+        writeStringArray(debugInfo.variableNames);
 
         writeMapping(debugInfo.fileMapping);
         writeMapping(debugInfo.lineMapping);
         writeMapping(debugInfo.classMapping);
         writeMapping(debugInfo.methodMapping);
+        writeUnsignedNumber(nonNullVariableMappings(debugInfo));
+        writeVariableMappings(debugInfo);
+    }
+
+    private void writeVariableMappings(DebugInformation debugInfo) throws IOException {
+        int lastVar = 0;
+        for (int i = 0; i < debugInfo.variableMappings.length; ++i) {
+            DebugInformation.Mapping mapping = debugInfo.variableMappings[i];
+            if (mapping == null) {
+                continue;
+            }
+            writeUnsignedNumber(i - lastVar);
+            lastVar = i;
+            writeMapping(mapping);
+        }
+    }
+
+    private int nonNullVariableMappings(DebugInformation debugInfo) {
+        int count = 0;
+        for (int i = 0; i < debugInfo.variableMappings.length; ++i) {
+            if (debugInfo.variableMappings[i] != null) {
+                ++count;
+            }
+        }
+        return count;
     }
 
     private void writeStringArray(String[] array) throws IOException {
diff --git a/teavm-core/src/main/java/org/teavm/debugging/Debugger.java b/teavm-core/src/main/java/org/teavm/debugging/Debugger.java
index 48dd77c78..eabab3b1b 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/Debugger.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/Debugger.java
@@ -186,7 +186,7 @@ public class Debugger {
                 MethodReference method = !empty ? debugInformation.getMethodAt(jsFrame.getLocation().getLine(),
                         jsFrame.getLocation().getColumn()) : null;
                 if (!empty || !wasEmpty) {
-                    frames.add(new CallFrame(loc, method));
+                    frames.add(new CallFrame(loc, method, new HashMap<String, LocalVariable>()));
                 }
                 wasEmpty = empty;
             }
diff --git a/teavm-core/src/main/java/org/teavm/debugging/DummyDebugInformationEmitter.java b/teavm-core/src/main/java/org/teavm/debugging/DummyDebugInformationEmitter.java
index 49d6e2c98..de84a96a2 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/DummyDebugInformationEmitter.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/DummyDebugInformationEmitter.java
@@ -36,6 +36,10 @@ public class DummyDebugInformationEmitter implements DebugInformationEmitter {
     public void emitClass(String className) {
     }
 
+    @Override
+    public void emitVariable(String sourceName, String generatedName) {
+    }
+
     @Override
     public void setLocationProvider(LocationProvider locationProvider) {
     }
diff --git a/teavm-core/src/main/java/org/teavm/debugging/JavaScriptCallFrame.java b/teavm-core/src/main/java/org/teavm/debugging/JavaScriptCallFrame.java
index a0a6d4c4a..a80e8aab2 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/JavaScriptCallFrame.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/JavaScriptCallFrame.java
@@ -15,10 +15,14 @@
  */
 package org.teavm.debugging;
 
+import java.util.Map;
+
 /**
  *
  * @author Alexey Andreev
  */
 public interface JavaScriptCallFrame {
     JavaScriptLocation getLocation();
+
+    Map<String, JavaScriptVariable> getVariables();
 }
diff --git a/teavm-core/src/main/java/org/teavm/debugging/JavaScriptValue.java b/teavm-core/src/main/java/org/teavm/debugging/JavaScriptValue.java
new file mode 100644
index 000000000..7541f781b
--- /dev/null
+++ b/teavm-core/src/main/java/org/teavm/debugging/JavaScriptValue.java
@@ -0,0 +1,13 @@
+package org.teavm.debugging;
+
+import java.util.Map;
+
+/**
+ *
+ * @author Alexey Andreev <konsoletyper@gmail.com>
+ */
+public interface JavaScriptValue {
+    String getRepresentation();
+
+    Map<String, JavaScriptVariable> getProperties();
+}
diff --git a/teavm-core/src/main/java/org/teavm/debugging/JavaScriptVariable.java b/teavm-core/src/main/java/org/teavm/debugging/JavaScriptVariable.java
new file mode 100644
index 000000000..511216f39
--- /dev/null
+++ b/teavm-core/src/main/java/org/teavm/debugging/JavaScriptVariable.java
@@ -0,0 +1,11 @@
+package org.teavm.debugging;
+
+/**
+ *
+ * @author Alexey Andreev <konsoletyper@gmail.com>
+ */
+public interface JavaScriptVariable {
+    String getName();
+
+    JavaScriptValue getValue();
+}
diff --git a/teavm-core/src/main/java/org/teavm/debugging/LocalVariable.java b/teavm-core/src/main/java/org/teavm/debugging/LocalVariable.java
new file mode 100644
index 000000000..e98029b55
--- /dev/null
+++ b/teavm-core/src/main/java/org/teavm/debugging/LocalVariable.java
@@ -0,0 +1,23 @@
+package org.teavm.debugging;
+
+/**
+ *
+ * @author Alexey Andreev <konsoletyper@gmail.com>
+ */
+public class LocalVariable {
+    private String name;
+    private WatchedValue value;
+
+    LocalVariable(String name, WatchedValue value) {
+        this.name = name;
+        this.value = value;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public WatchedValue getValue() {
+        return value;
+    }
+}
diff --git a/teavm-core/src/main/java/org/teavm/debugging/WatchedValue.java b/teavm-core/src/main/java/org/teavm/debugging/WatchedValue.java
new file mode 100644
index 000000000..bf44a8410
--- /dev/null
+++ b/teavm-core/src/main/java/org/teavm/debugging/WatchedValue.java
@@ -0,0 +1,13 @@
+package org.teavm.debugging;
+
+import java.util.Map;
+
+/**
+ *
+ * @author Alexey Andreev <konsoletyper@gmail.com>
+ */
+public abstract class WatchedValue {
+    public abstract String getRepresentation();
+
+    public abstract Map<String, LocalVariable> getProperties();
+}
diff --git a/teavm-core/src/main/java/org/teavm/javascript/Decompiler.java b/teavm-core/src/main/java/org/teavm/javascript/Decompiler.java
index a7e186502..74f104fc2 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/Decompiler.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/Decompiler.java
@@ -268,6 +268,11 @@ public class Decompiler {
         Optimizer optimizer = new Optimizer();
         optimizer.optimize(methodNode, method.getProgram());
         methodNode.getModifiers().addAll(mapModifiers(method.getModifiers()));
+        int paramCount = method.getSignature().length;
+        for (int i = 0; i < paramCount; ++i) {
+            Variable var = program.variableAt(i);
+            methodNode.getParameterDebugNames().add(var.getDebugName());
+        }
         return methodNode;
     }
 
diff --git a/teavm-core/src/main/java/org/teavm/javascript/NullPointerExceptionTransformer.java b/teavm-core/src/main/java/org/teavm/javascript/NullPointerExceptionTransformer.java
index f915886d9..59d872a8f 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/NullPointerExceptionTransformer.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/NullPointerExceptionTransformer.java
@@ -49,7 +49,7 @@ public class NullPointerExceptionTransformer implements ClassHolderTransformer {
                 }
                 NullCheckInstruction nullCheck = new NullCheckInstruction();
                 nullCheck.setValue(invoke.getInstance());
-                Variable var = block.getProgram().createVariable();
+                Variable var = block.getProgram().createVariable(null);
                 nullCheck.setReceiver(var);
                 invoke.setInstance(var);
                 block.getInstructions().add(i++, nullCheck);
diff --git a/teavm-core/src/main/java/org/teavm/javascript/Renderer.java b/teavm-core/src/main/java/org/teavm/javascript/Renderer.java
index 695c90b1d..e5fafbd71 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/Renderer.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/Renderer.java
@@ -518,6 +518,9 @@ public class Renderer implements ExprVisitor, StatementVisitor, RenderingContext
         public void visit(RegularMethodNode method) {
             try {
                 MethodReference ref = method.getReference();
+                for (int i = 0; i < method.getParameterDebugNames().size(); ++i) {
+                    debugEmitter.emitVariable(method.getParameterDebugNames().get(i), variableName(i));
+                }
                 int variableCount = 0;
                 for (int var : method.getVariables()) {
                     variableCount = Math.max(variableCount, var + 1);
@@ -601,6 +604,10 @@ public class Renderer implements ExprVisitor, StatementVisitor, RenderingContext
             if (statement.getLocation() != null) {
                 popLocation();
             }
+            if (statement.getLeftValue() instanceof VariableExpr) {
+                VariableExpr receiver = (VariableExpr)statement.getLeftValue();
+                debugEmitter.emitVariable(statement.getDebugName(), variableName(receiver.getIndex()));
+            }
         } catch (IOException e) {
             throw new RenderingException("IO error occured", e);
         }
diff --git a/teavm-core/src/main/java/org/teavm/javascript/StatementGenerator.java b/teavm-core/src/main/java/org/teavm/javascript/StatementGenerator.java
index aaf3e8b2f..20444591f 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/StatementGenerator.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/StatementGenerator.java
@@ -48,44 +48,44 @@ class StatementGenerator implements InstructionVisitor {
 
     @Override
     public void visit(ClassConstantInstruction insn) {
-        assign(Expr.constant(insn.getConstant()), insn.getReceiver().getIndex());
+        assign(Expr.constant(insn.getConstant()), insn.getReceiver());
     }
 
     @Override
     public void visit(NullConstantInstruction insn) {
-        assign(Expr.constant(null), insn.getReceiver().getIndex());
+        assign(Expr.constant(null), insn.getReceiver());
     }
 
     @Override
     public void visit(IntegerConstantInstruction insn) {
-        assign(Expr.constant(insn.getConstant()), insn.getReceiver().getIndex());
+        assign(Expr.constant(insn.getConstant()), insn.getReceiver());
     }
 
     @Override
     public void visit(LongConstantInstruction insn) {
-        assign(Expr.constant(insn.getConstant()), insn.getReceiver().getIndex());
+        assign(Expr.constant(insn.getConstant()), insn.getReceiver());
     }
 
     @Override
     public void visit(FloatConstantInstruction insn) {
-        assign(Expr.constant(insn.getConstant()), insn.getReceiver().getIndex());
+        assign(Expr.constant(insn.getConstant()), insn.getReceiver());
     }
 
     @Override
     public void visit(DoubleConstantInstruction insn) {
-        assign(Expr.constant(insn.getConstant()), insn.getReceiver().getIndex());
+        assign(Expr.constant(insn.getConstant()), insn.getReceiver());
     }
 
     @Override
     public void visit(StringConstantInstruction insn) {
-        assign(Expr.constant(insn.getConstant()), insn.getReceiver().getIndex());
+        assign(Expr.constant(insn.getConstant()), insn.getReceiver());
     }
 
     @Override
     public void visit(BinaryInstruction insn) {
         int first = insn.getFirstOperand().getIndex();
         int second = insn.getSecondOperand().getIndex();
-        int result = insn.getReceiver().getIndex();
+        Variable result = insn.getReceiver();
         switch (insn.getOperation()) {
             case ADD:
                 switch (insn.getOperandType()) {
@@ -227,15 +227,15 @@ class StatementGenerator implements InstructionVisitor {
         switch (insn.getOperandType()) {
             case INT:
                 assign(castToInteger(Expr.unary(UnaryOperation.NEGATE, Expr.var(insn.getOperand().getIndex()))),
-                        insn.getReceiver().getIndex());
+                        insn.getReceiver());
                 break;
             case LONG:
                 assign(Expr.unary(UnaryOperation.NEGATE_LONG, Expr.var(insn.getOperand().getIndex())),
-                        insn.getReceiver().getIndex());
+                        insn.getReceiver());
                 break;
             default:
                 assign(Expr.unary(UnaryOperation.NEGATE, Expr.var(insn.getOperand().getIndex())),
-                        insn.getReceiver().getIndex());
+                        insn.getReceiver());
                 break;
         }
     }
@@ -244,13 +244,14 @@ class StatementGenerator implements InstructionVisitor {
     public void visit(AssignInstruction insn) {
         AssignmentStatement stmt = Statement.assign(Expr.var(insn.getReceiver().getIndex()),
                 Expr.var(insn.getAssignee().getIndex()));
+        stmt.setDebugName(insn.getReceiver().getDebugName());
         stmt.setLocation(currentLocation);
         statements.add(stmt);
     }
 
     @Override
     public void visit(CastInstruction insn) {
-        assign(Expr.var(insn.getValue().getIndex()), insn.getReceiver().getIndex());
+        assign(Expr.var(insn.getValue().getIndex()), insn.getReceiver());
     }
 
     @Override
@@ -292,7 +293,7 @@ class StatementGenerator implements InstructionVisitor {
             default:
                 break;
         }
-        assign(value, insn.getReceiver().getIndex());
+        assign(value, insn.getReceiver());
     }
 
     @Override
@@ -323,7 +324,7 @@ class StatementGenerator implements InstructionVisitor {
                 }
                 break;
         }
-        assign(value, insn.getReceiver().getIndex());
+        assign(value, insn.getReceiver());
     }
 
     @Override
@@ -459,13 +460,12 @@ class StatementGenerator implements InstructionVisitor {
 
     @Override
     public void visit(ConstructArrayInstruction insn) {
-        assign(Expr.createArray(insn.getItemType(), Expr.var(insn.getSize().getIndex())),
-                insn.getReceiver().getIndex());
+        assign(Expr.createArray(insn.getItemType(), Expr.var(insn.getSize().getIndex())), insn.getReceiver());
     }
 
     @Override
     public void visit(ConstructInstruction insn) {
-        assign(Expr.createObject(insn.getType()), insn.getReceiver().getIndex());
+        assign(Expr.createObject(insn.getType()), insn.getReceiver());
     }
 
     @Override
@@ -474,7 +474,7 @@ class StatementGenerator implements InstructionVisitor {
         for (int i = 0; i < dimensionExprs.length; ++i) {
             dimensionExprs[i] = Expr.var(insn.getDimensions().get(i).getIndex());
         }
-        assign(Expr.createArray(insn.getItemType(), dimensionExprs), insn.getReceiver().getIndex());
+        assign(Expr.createArray(insn.getItemType(), dimensionExprs), insn.getReceiver());
     }
 
     @Override
@@ -509,28 +509,27 @@ class StatementGenerator implements InstructionVisitor {
 
     @Override
     public void visit(ArrayLengthInstruction insn) {
-        assign(Expr.unary(UnaryOperation.LENGTH, Expr.var(insn.getArray().getIndex())), insn.getReceiver().getIndex());
+        assign(Expr.unary(UnaryOperation.LENGTH, Expr.var(insn.getArray().getIndex())), insn.getReceiver());
     }
 
     @Override
     public void visit(UnwrapArrayInstruction insn) {
         UnwrapArrayExpr unwrapExpr = new UnwrapArrayExpr(insn.getElementType());
         unwrapExpr.setArray(Expr.var(insn.getArray().getIndex()));
-        assign(unwrapExpr, insn.getReceiver().getIndex());
+        assign(unwrapExpr, insn.getReceiver());
     }
 
     @Override
     public void visit(CloneArrayInstruction insn) {
         MethodDescriptor cloneMethodDesc = new MethodDescriptor("clone", ValueType.object("java.lang.Object"));
         MethodReference cloneMethod = new MethodReference("java.lang.Object", cloneMethodDesc);
-        assign(Expr.invoke(cloneMethod, Expr.var(insn.getArray().getIndex()), new Expr[0]),
-                insn.getReceiver().getIndex());
+        assign(Expr.invoke(cloneMethod, Expr.var(insn.getArray().getIndex()), new Expr[0]), insn.getReceiver());
     }
 
     @Override
     public void visit(GetElementInstruction insn) {
         assign(Expr.subscript(Expr.var(insn.getArray().getIndex()), Expr.var(insn.getIndex().getIndex())),
-                insn.getReceiver().getIndex());
+                insn.getReceiver());
     }
 
     @Override
@@ -559,7 +558,7 @@ class StatementGenerator implements InstructionVisitor {
             invocationExpr = Expr.invokeStatic(insn.getMethod(), exprArgs);
         }
         if (insn.getReceiver() != null) {
-            assign(invocationExpr, insn.getReceiver().getIndex());
+            assign(invocationExpr, insn.getReceiver());
         } else {
             AssignmentStatement stmt = Statement.assign(null, invocationExpr);
             stmt.setLocation(currentLocation);
@@ -569,13 +568,13 @@ class StatementGenerator implements InstructionVisitor {
 
     @Override
     public void visit(IsInstanceInstruction insn) {
-        assign(Expr.instanceOf(Expr.var(insn.getValue().getIndex()), insn.getType()),
-                insn.getReceiver().getIndex());
+        assign(Expr.instanceOf(Expr.var(insn.getValue().getIndex()), insn.getType()), insn.getReceiver());
     }
 
-    private void assign(Expr source, int target) {
-        AssignmentStatement stmt = Statement.assign(Expr.var(target), source);
+    private void assign(Expr source, Variable target) {
+        AssignmentStatement stmt = Statement.assign(Expr.var(target.getIndex()), source);
         stmt.setLocation(currentLocation);
+        stmt.setDebugName(target.getDebugName());
         statements.add(stmt);
     }
 
@@ -599,11 +598,11 @@ class StatementGenerator implements InstructionVisitor {
         return Expr.unary(UnaryOperation.LONG_TO_NUM, value);
     }
 
-    private void binary(int first, int second, int result, BinaryOperation op) {
+    private void binary(int first, int second, Variable result, BinaryOperation op) {
         assign(Expr.binary(op, Expr.var(first), Expr.var(second)), result);
     }
 
-    private void intBinary(int first, int second, int result, BinaryOperation op) {
+    private void intBinary(int first, int second, Variable result, BinaryOperation op) {
         assign(castToInteger(Expr.binary(op, Expr.var(first), Expr.var(second))), result);
     }
 
@@ -657,7 +656,6 @@ class StatementGenerator implements InstructionVisitor {
 
     @Override
     public void visit(NullCheckInstruction insn) {
-        assign(Expr.unary(UnaryOperation.NULL_CHECK, Expr.var(insn.getValue().getIndex())),
-                insn.getReceiver().getIndex());
+        assign(Expr.unary(UnaryOperation.NULL_CHECK, Expr.var(insn.getValue().getIndex())), insn.getReceiver());
     }
 }
diff --git a/teavm-core/src/main/java/org/teavm/javascript/ast/AssignmentStatement.java b/teavm-core/src/main/java/org/teavm/javascript/ast/AssignmentStatement.java
index 49f670f8b..f76b6465e 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/ast/AssignmentStatement.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/ast/AssignmentStatement.java
@@ -23,6 +23,7 @@ public class AssignmentStatement extends Statement {
     private Expr leftValue;
     private Expr rightValue;
     private NodeLocation location;
+    private String debugName;
 
     public Expr getLeftValue() {
         return leftValue;
@@ -48,6 +49,14 @@ public class AssignmentStatement extends Statement {
         this.location = location;
     }
 
+    public String getDebugName() {
+        return debugName;
+    }
+
+    public void setDebugName(String debugName) {
+        this.debugName = debugName;
+    }
+
     @Override
     public void acceptVisitor(StatementVisitor visitor) {
         visitor.visit(this);
diff --git a/teavm-core/src/main/java/org/teavm/javascript/ast/RegularMethodNode.java b/teavm-core/src/main/java/org/teavm/javascript/ast/RegularMethodNode.java
index 8184d8fac..f37a9ccb4 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/ast/RegularMethodNode.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/ast/RegularMethodNode.java
@@ -26,6 +26,7 @@ import org.teavm.model.MethodReference;
 public class RegularMethodNode extends MethodNode {
     private Statement body;
     private List<Integer> variables = new ArrayList<>();
+    private List<String> parameterDebugNames = new ArrayList<>();
 
     public RegularMethodNode(MethodReference reference) {
         super(reference);
@@ -43,6 +44,10 @@ public class RegularMethodNode extends MethodNode {
         return variables;
     }
 
+    public List<String> getParameterDebugNames() {
+        return parameterDebugNames;
+    }
+
     @Override
     public void acceptVisitor(MethodNodeVisitor visitor) {
         visitor.visit(this);
diff --git a/teavm-core/src/main/java/org/teavm/model/Program.java b/teavm-core/src/main/java/org/teavm/model/Program.java
index 9c3cab944..ffb05aa15 100644
--- a/teavm-core/src/main/java/org/teavm/model/Program.java
+++ b/teavm-core/src/main/java/org/teavm/model/Program.java
@@ -35,8 +35,8 @@ public class Program implements ProgramReader {
         return block;
     }
 
-    public Variable createVariable() {
-        Variable variable = new Variable(this);
+    public Variable createVariable(String debugName) {
+        Variable variable = new Variable(this, debugName);
         variable.setIndex(variables.size());
         variables.add(variable);
         variable.setRegister(lastUsedRegister++);
diff --git a/teavm-core/src/main/java/org/teavm/model/Variable.java b/teavm-core/src/main/java/org/teavm/model/Variable.java
index ceb63fc01..2708f68a0 100644
--- a/teavm-core/src/main/java/org/teavm/model/Variable.java
+++ b/teavm-core/src/main/java/org/teavm/model/Variable.java
@@ -23,9 +23,11 @@ public class Variable implements VariableReader {
     private Program program;
     private int index;
     private int register;
+    private String debugName;
 
-    Variable(Program program) {
+    Variable(Program program, String debugName) {
         this.program = program;
+        this.debugName = debugName;
     }
 
     @Override
@@ -54,4 +56,13 @@ public class Variable implements VariableReader {
     public void setRegister(int register) {
         this.register = register;
     }
+
+    @Override
+    public String getDebugName() {
+        return debugName;
+    }
+
+    public void setDebugName(String debugName) {
+        this.debugName = debugName;
+    }
 }
diff --git a/teavm-core/src/main/java/org/teavm/model/VariableReader.java b/teavm-core/src/main/java/org/teavm/model/VariableReader.java
index d93ed618e..a62aaa3d7 100644
--- a/teavm-core/src/main/java/org/teavm/model/VariableReader.java
+++ b/teavm-core/src/main/java/org/teavm/model/VariableReader.java
@@ -24,5 +24,7 @@ public interface VariableReader {
 
     ProgramReader getProgram();
 
+    String getDebugName();
+
     int getRegister();
 }
diff --git a/teavm-core/src/main/java/org/teavm/model/util/ProgramUtils.java b/teavm-core/src/main/java/org/teavm/model/util/ProgramUtils.java
index 7ec26790e..ec2bffac6 100644
--- a/teavm-core/src/main/java/org/teavm/model/util/ProgramUtils.java
+++ b/teavm-core/src/main/java/org/teavm/model/util/ProgramUtils.java
@@ -73,7 +73,7 @@ public final class ProgramUtils {
         InstructionCopyReader insnCopier = new InstructionCopyReader();
         insnCopier.programCopy = copy;
         for (int i = 0; i < program.variableCount(); ++i) {
-            copy.createVariable();
+            copy.createVariable(program.variableAt(i).getDebugName());
         }
         for (int i = 0; i < program.basicBlockCount(); ++i) {
             copy.createBasicBlock();
diff --git a/teavm-core/src/main/java/org/teavm/model/util/RegisterAllocator.java b/teavm-core/src/main/java/org/teavm/model/util/RegisterAllocator.java
index 946fdf740..5d74f3c5a 100644
--- a/teavm-core/src/main/java/org/teavm/model/util/RegisterAllocator.java
+++ b/teavm-core/src/main/java/org/teavm/model/util/RegisterAllocator.java
@@ -97,7 +97,7 @@ public class RegisterAllocator {
         final Phi phi = incoming.getPhi();
         Program program = phi.getBasicBlock().getProgram();
         AssignInstruction copyInstruction = new AssignInstruction();
-        Variable firstCopy = program.createVariable();
+        Variable firstCopy = program.createVariable(incoming.getValue().getDebugName());
         copyInstruction.setReceiver(firstCopy);
         copyInstruction.setAssignee(incoming.getValue());
         BasicBlock source = blockMap.get(incoming.getSource());
diff --git a/teavm-core/src/main/java/org/teavm/optimization/LoopInvariantMotion.java b/teavm-core/src/main/java/org/teavm/optimization/LoopInvariantMotion.java
index 32b7da2c7..4cc8c979e 100644
--- a/teavm-core/src/main/java/org/teavm/optimization/LoopInvariantMotion.java
+++ b/teavm-core/src/main/java/org/teavm/optimization/LoopInvariantMotion.java
@@ -179,7 +179,7 @@ public class LoopInvariantMotion implements MethodOptimization {
                     phi.getIncomings().remove(j--);
                     if (preheaderPhi == null) {
                         preheaderPhi = new Phi();
-                        preheaderPhi.setReceiver(program.createVariable());
+                        preheaderPhi.setReceiver(program.createVariable(null));
                         preheader.getPhis().add(preheaderPhi);
                     }
                     preheaderPhi.getIncomings().add(incoming);
@@ -391,7 +391,7 @@ public class LoopInvariantMotion implements MethodOptimization {
 
         @Override
         public void visit(ClassConstantInstruction insn) {
-            var = program.createVariable();
+            var = program.createVariable(insn.getReceiver().getDebugName());
             ClassConstantInstruction copy = new ClassConstantInstruction();
             copy.setConstant(insn.getConstant());
             copy.setReceiver(var);
@@ -400,7 +400,7 @@ public class LoopInvariantMotion implements MethodOptimization {
 
         @Override
         public void visit(NullConstantInstruction insn) {
-            var = program.createVariable();
+            var = program.createVariable(insn.getReceiver().getDebugName());
             NullConstantInstruction copy = new NullConstantInstruction();
             copy.setReceiver(var);
             this.copy = copy;
@@ -408,7 +408,7 @@ public class LoopInvariantMotion implements MethodOptimization {
 
         @Override
         public void visit(IntegerConstantInstruction insn) {
-            var = program.createVariable();
+            var = program.createVariable(insn.getReceiver().getDebugName());
             IntegerConstantInstruction copy = new IntegerConstantInstruction();
             copy.setConstant(insn.getConstant());
             copy.setReceiver(var);
@@ -417,7 +417,7 @@ public class LoopInvariantMotion implements MethodOptimization {
 
         @Override
         public void visit(LongConstantInstruction insn) {
-            var = program.createVariable();
+            var = program.createVariable(insn.getReceiver().getDebugName());
             LongConstantInstruction copy = new LongConstantInstruction();
             copy.setConstant(insn.getConstant());
             copy.setReceiver(var);
@@ -426,7 +426,7 @@ public class LoopInvariantMotion implements MethodOptimization {
 
         @Override
         public void visit(FloatConstantInstruction insn) {
-            var = program.createVariable();
+            var = program.createVariable(insn.getReceiver().getDebugName());
             FloatConstantInstruction copy = new FloatConstantInstruction();
             copy.setConstant(insn.getConstant());
             copy.setReceiver(var);
@@ -435,7 +435,7 @@ public class LoopInvariantMotion implements MethodOptimization {
 
         @Override
         public void visit(DoubleConstantInstruction insn) {
-            var = program.createVariable();
+            var = program.createVariable(insn.getReceiver().getDebugName());
             DoubleConstantInstruction copy = new DoubleConstantInstruction();
             copy.setConstant(insn.getConstant());
             copy.setReceiver(var);
@@ -444,7 +444,7 @@ public class LoopInvariantMotion implements MethodOptimization {
 
         @Override
         public void visit(StringConstantInstruction insn) {
-            var = program.createVariable();
+            var = program.createVariable(insn.getReceiver().getDebugName());
             StringConstantInstruction copy = new StringConstantInstruction();
             copy.setConstant(insn.getConstant());
             copy.setReceiver(var);
diff --git a/teavm-core/src/main/java/org/teavm/parsing/Parser.java b/teavm-core/src/main/java/org/teavm/parsing/Parser.java
index e8d647ed8..e01940cda 100644
--- a/teavm-core/src/main/java/org/teavm/parsing/Parser.java
+++ b/teavm-core/src/main/java/org/teavm/parsing/Parser.java
@@ -40,11 +40,11 @@ public final class Parser {
         Program program = programParser.parse(node, className);
         new UnreachableBasicBlockEliminator().optimize(program);
         SSATransformer ssaProducer = new SSATransformer();
-        ssaProducer.transformToSSA(program, method.getParameterTypes());
+        ssaProducer.transformToSSA(program, programParser, method.getParameterTypes());
         method.setProgram(program);
         parseAnnotations(method.getAnnotations(), node.visibleAnnotations, node.invisibleAnnotations);
         while (program.variableCount() <= method.parameterCount()) {
-            program.createVariable();
+            program.createVariable(null);
         }
         return method;
     }
diff --git a/teavm-core/src/main/java/org/teavm/parsing/ProgramParser.java b/teavm-core/src/main/java/org/teavm/parsing/ProgramParser.java
index 43842868c..c18cb3fee 100644
--- a/teavm-core/src/main/java/org/teavm/parsing/ProgramParser.java
+++ b/teavm-core/src/main/java/org/teavm/parsing/ProgramParser.java
@@ -20,13 +20,14 @@ import org.objectweb.asm.*;
 import org.objectweb.asm.tree.*;
 import org.teavm.model.*;
 import org.teavm.model.instructions.*;
+import org.teavm.model.util.DefinitionExtractor;
 import org.teavm.model.util.InstructionTransitionExtractor;
 
 /**
  *
  * @author Alexey Andreev
  */
-public class ProgramParser {
+public class ProgramParser implements VariableDebugInformation {
     static final byte ROOT = 0;
     static final byte SINGLE = 1;
     static final byte DOUBLE_FIRST_HALF = 2;
@@ -48,6 +49,9 @@ public class ProgramParser {
     private int currentLineNumber;
     private boolean lineNumberChanged;
     private InstructionLocation lastInsnLocation;
+    private Map<Integer, List<LocalVariableNode>> localVariableMap = new HashMap<>();
+    private Map<Instruction, String> variableDebugNames = new HashMap<>();
+    private Map<Integer, String> parameterNames = new HashMap<>();
 
     private static class Step {
         public final int source;
@@ -113,11 +117,29 @@ public class ProgramParser {
         }
         int signatureVars = countSignatureVariables(method.desc);
         while (program.variableCount() <= signatureVars) {
-            program.createVariable();
+            program.createVariable(getVariableDebugName(program.variableCount(), 0));
+        }
+        for (int i = 0; i < signatureVars; ++i) {
+            parameterNames.put(i, getVariableDebugName(i, 0));
         }
         return program;
     }
 
+    private String getVariableDebugName(int var, int location) {
+        List<LocalVariableNode> nodes = localVariableMap.get(var);
+        if (nodes == null) {
+            return null;
+        }
+        for (LocalVariableNode node : nodes) {
+            int start = labelIndexes.get(node.start.getLabel());
+            int end = labelIndexes.get(node.end.getLabel());
+            if (location >= start && location < end) {
+                return node.name;
+            }
+        }
+        return null;
+    }
+
     private int countSignatureVariables(String desc) {
         int count = 1;
         for (Type paramType : Type.getArgumentTypes(desc)) {
@@ -159,6 +181,16 @@ public class ProgramParser {
         return depth;
     }
 
+    @Override
+    public String getDefinitionDebugName(Instruction insn) {
+        return variableDebugNames.get(insn);
+    }
+
+    @Override
+    public String getParameterDebugName(int index) {
+        return parameterNames.get(index);
+    }
+
     private void prepare(MethodNode method) {
         InsnList instructions = method.instructions;
         minLocal = 0;
@@ -177,6 +209,14 @@ public class ProgramParser {
                 lineNumbers.put(lineNumberNode.start.getLabel(), lineNumberNode.line);
             }
         }
+        for (LocalVariableNode localVar : method.localVariables) {
+            List<LocalVariableNode> vars = localVariableMap.get(localVar.index);
+            if (vars == null) {
+                vars = new ArrayList<>();
+                localVariableMap.put(localVar.index, vars);
+            }
+            vars.add(localVar);
+        }
         targetInstructions = new ArrayList<>(instructions.size());
         targetInstructions.addAll(Collections.<List<Instruction>>nCopies(instructions.size(), null));
         basicBlocks.addAll(Collections.<BasicBlock>nCopies(instructions.size(), null));
@@ -250,6 +290,20 @@ public class ProgramParser {
     }
 
     private void assemble() {
+        DefinitionExtractor defExtractor = new DefinitionExtractor();
+        for (int i = 0; i < targetInstructions.size(); ++i) {
+            List<Instruction> instructionList = targetInstructions.get(i);
+            for (Instruction insn : instructionList) {
+                insn.acceptVisitor(defExtractor);
+                for (Variable var : defExtractor.getDefinedVariables()) {
+                    String debugName = getVariableDebugName(var.getIndex(), i);
+                    if (debugName != null) {
+                        variableDebugNames.put(insn, debugName);
+                    }
+                }
+            }
+        }
+
         BasicBlock basicBlock = null;
         for (int i = 0; i < basicBlocks.size(); ++i) {
             BasicBlock newBasicBlock = basicBlocks.get(i);
@@ -300,7 +354,7 @@ public class ProgramParser {
 
     private Variable getVariable(int index) {
         while (index >= program.variableCount()) {
-            program.createVariable();
+            program.createVariable(null);
         }
         return program.variableAt(index);
     }
diff --git a/teavm-core/src/main/java/org/teavm/parsing/SSATransformer.java b/teavm-core/src/main/java/org/teavm/parsing/SSATransformer.java
index 46d93dbc0..af0e333c0 100644
--- a/teavm-core/src/main/java/org/teavm/parsing/SSATransformer.java
+++ b/teavm-core/src/main/java/org/teavm/parsing/SSATransformer.java
@@ -38,12 +38,14 @@ public class SSATransformer {
     private Phi[][] phiMap;
     private int[][] phiIndexMap;
     private ValueType[] arguments;
+    private VariableDebugInformation variableDebugInfo;
 
-    public void transformToSSA(Program program, ValueType[] arguments) {
+    public void transformToSSA(Program program, VariableDebugInformation variableDebugInfo, ValueType[] arguments) {
         if (program.basicBlockCount() == 0) {
             return;
         }
         this.program = program;
+        this.variableDebugInfo = variableDebugInfo;
         this.arguments = arguments;
         cfg = ProgramUtils.buildControlFlowGraphWithoutTryCatch(program);
         domTree = GraphUtils.buildDominatorTree(cfg);
@@ -55,6 +57,9 @@ public class SSATransformer {
             phiMap[i] = new Phi[program.variableCount()];
             phiIndexMap[i] = new int[program.variableCount()];
         }
+        for (int i = 0; i < program.variableCount(); ++i) {
+            program.variableAt(i).setDebugName(variableDebugInfo.getParameterDebugName(i));
+        }
         applySignature();
         domFrontiers = GraphUtils.findDominanceFrontiers(cfg, domTree);
         estimatePhis();
@@ -136,16 +141,17 @@ public class SSATransformer {
             processed[currentBlock.getIndex()] = true;
             variableMap = Arrays.copyOf(task.variables, task.variables.length);
             for (Phi phi : currentBlock.getPhis()) {
-                Variable var = program.createVariable();
+                Variable var = program.createVariable(phi.getReceiver().getDebugName());
                 variableMap[phi.getReceiver().getIndex()] = var;
                 phi.setReceiver(var);
             }
             if (!caughtBlocks.get(currentBlock.getIndex()).isEmpty()) {
                 Phi phi = new Phi();
-                phi.setReceiver(program.createVariable());
+                phi.setReceiver(program.createVariable(null));
                 for (TryCatchBlock tryCatch : caughtBlocks.get(currentBlock.getIndex())) {
                     variableMap[tryCatch.getExceptionVariable().getIndex()] = phi.getReceiver();
-                    tryCatch.setExceptionVariable(program.createVariable());
+                    tryCatch.setExceptionVariable(program.createVariable(
+                            tryCatch.getExceptionVariable().getDebugName()));
                     Incoming incoming = new Incoming();
                     incoming.setSource(tryCatch.getProtectedBlock());
                     incoming.setValue(tryCatch.getExceptionVariable());
@@ -210,8 +216,8 @@ public class SSATransformer {
         }
     }
 
-    private Variable define(Variable var) {
-        Variable result = program.createVariable();
+    private Variable define(Variable var, String debugName) {
+        Variable result = program.createVariable(debugName);
         variableMap[var.getIndex()] = result;
         return result;
     }
@@ -231,56 +237,56 @@ public class SSATransformer {
 
         @Override
         public void visit(ClassConstantInstruction insn) {
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(NullConstantInstruction insn) {
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(IntegerConstantInstruction insn) {
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(LongConstantInstruction insn) {
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(FloatConstantInstruction insn) {
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(DoubleConstantInstruction insn) {
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(StringConstantInstruction insn) {
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(BinaryInstruction insn) {
             insn.setFirstOperand(use(insn.getFirstOperand()));
             insn.setSecondOperand(use(insn.getSecondOperand()));
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(NegateInstruction insn) {
             insn.setOperand(use(insn.getOperand()));
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(AssignInstruction insn) {
             insn.setAssignee(use(insn.getAssignee()));
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
@@ -318,12 +324,12 @@ public class SSATransformer {
         @Override
         public void visit(ConstructArrayInstruction insn) {
             insn.setSize(use(insn.getSize()));
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(ConstructInstruction insn) {
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
@@ -332,7 +338,7 @@ public class SSATransformer {
             for (int i = 0; i < dimensions.size(); ++i) {
                 dimensions.set(i, use(dimensions.get(i)));
             }
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
@@ -340,7 +346,7 @@ public class SSATransformer {
             if (insn.getInstance() != null) {
                 insn.setInstance(use(insn.getInstance()));
             }
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
@@ -355,7 +361,7 @@ public class SSATransformer {
         public void visit(GetElementInstruction insn) {
             insn.setArray(use(insn.getArray()));
             insn.setIndex(use(insn.getIndex()));
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
@@ -375,50 +381,50 @@ public class SSATransformer {
                 insn.setInstance(use(insn.getInstance()));
             }
             if (insn.getReceiver() != null) {
-                insn.setReceiver(define(insn.getReceiver()));
+                insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
             }
         }
 
         @Override
         public void visit(IsInstanceInstruction insn) {
             insn.setValue(use(insn.getValue()));
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(CastInstruction insn) {
             insn.setValue(use(insn.getValue()));
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(CastNumberInstruction insn) {
             insn.setValue(use(insn.getValue()));
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(CastIntegerInstruction insn) {
             insn.setValue(use(insn.getValue()));
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(ArrayLengthInstruction insn) {
             insn.setArray(use(insn.getArray()));
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(UnwrapArrayInstruction insn) {
             insn.setArray(use(insn.getArray()));
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
         public void visit(CloneArrayInstruction insn) {
             insn.setArray(use(insn.getArray()));
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
 
         @Override
@@ -428,7 +434,7 @@ public class SSATransformer {
         @Override
         public void visit(NullCheckInstruction insn) {
             insn.setValue(use(insn.getValue()));
-            insn.setReceiver(define(insn.getReceiver()));
+            insn.setReceiver(define(insn.getReceiver(), variableDebugInfo.getDefinitionDebugName(insn)));
         }
     };
 }
diff --git a/teavm-core/src/main/java/org/teavm/parsing/VariableDebugInformation.java b/teavm-core/src/main/java/org/teavm/parsing/VariableDebugInformation.java
new file mode 100644
index 000000000..db11c723e
--- /dev/null
+++ b/teavm-core/src/main/java/org/teavm/parsing/VariableDebugInformation.java
@@ -0,0 +1,13 @@
+package org.teavm.parsing;
+
+import org.teavm.model.Instruction;
+
+/**
+ *
+ * @author Alexey Andreev <konsoletyper@gmail.com>
+ */
+public interface VariableDebugInformation {
+    String getDefinitionDebugName(Instruction insn);
+
+    String getParameterDebugName(int index);
+}
diff --git a/teavm-html4j/src/main/java/org/teavm/html4j/JCLHacks.java b/teavm-html4j/src/main/java/org/teavm/html4j/JCLHacks.java
index 7a0cbd850..2c4557a3f 100644
--- a/teavm-html4j/src/main/java/org/teavm/html4j/JCLHacks.java
+++ b/teavm-html4j/src/main/java/org/teavm/html4j/JCLHacks.java
@@ -44,13 +44,13 @@ public class JCLHacks implements ClassHolderTransformer {
         MethodHolder method = new MethodHolder(desc);
         Program program = new Program();
         for (int i = 0; i < desc.parameterCount(); ++i) {
-            program.createVariable();
+            program.createVariable(null);
         }
         if (!staticMethod) {
-            program.createVariable();
+            program.createVariable(null);
         }
-        program.createVariable();
-        Variable var = program.createVariable();
+        program.createVariable(null);
+        Variable var = program.createVariable(null);
         BasicBlock block = program.createBasicBlock();
         ConstructInstruction cons = new ConstructInstruction();
         cons.setType("java.lang.SecurityException");
@@ -75,8 +75,8 @@ public class JCLHacks implements ClassHolderTransformer {
     private MethodHolder createThreadSleep() {
         MethodHolder method = new MethodHolder("sleep", ValueType.LONG, ValueType.VOID);
         Program program = new Program();
-        program.createVariable();
-        program.createVariable();
+        program.createVariable(null);
+        program.createVariable(null);
         BasicBlock block = program.createBasicBlock();
         ExitInstruction exit = new ExitInstruction();
         block.getInstructions().add(exit);
diff --git a/teavm-jso/src/main/java/org/teavm/jso/plugin/JavascriptNativeProcessor.java b/teavm-jso/src/main/java/org/teavm/jso/plugin/JavascriptNativeProcessor.java
index 73e6a0971..1f50781c6 100644
--- a/teavm-jso/src/main/java/org/teavm/jso/plugin/JavascriptNativeProcessor.java
+++ b/teavm-jso/src/main/java/org/teavm/jso/plugin/JavascriptNativeProcessor.java
@@ -81,7 +81,7 @@ class JavascriptNativeProcessor {
                     if (isProperGetter(method.getDescriptor())) {
                         String propertyName = method.getName().charAt(0) == 'i' ? cutPrefix(method.getName(), 2) :
                                 cutPrefix(method.getName(), 3);
-                        Variable result = invoke.getReceiver() != null ? program.createVariable() : null;
+                        Variable result = invoke.getReceiver() != null ? program.createVariable(null) : null;
                         addPropertyGet(propertyName, invoke.getInstance(), result);
                         if (result != null) {
                             result = unwrap(result, method.getResultType());
@@ -96,7 +96,7 @@ class JavascriptNativeProcessor {
                     }
                 } else if (method.getAnnotations().get(JSIndexer.class.getName()) != null) {
                     if (isProperGetIndexer(method.getDescriptor())) {
-                        Variable result = invoke.getReceiver() != null ? program.createVariable() : null;
+                        Variable result = invoke.getReceiver() != null ? program.createVariable(null) : null;
                         addIndexerGet(invoke.getInstance(), wrap(invoke.getArguments().get(0),
                                 method.parameterType(0)), result);
                         if (result != null) {
@@ -143,7 +143,7 @@ class JavascriptNativeProcessor {
                                     "a proper native JavaScript method or constructor declaration");
                         }
                     }
-                    Variable result = invoke.getReceiver() != null ? program.createVariable() : null;
+                    Variable result = invoke.getReceiver() != null ? program.createVariable(null) : null;
                     InvokeInstruction newInvoke = new InvokeInstruction();
                     ValueType[] signature = new ValueType[method.parameterCount() + 3];
                     Arrays.fill(signature, ValueType.object(JSObject.class.getName()));
@@ -226,7 +226,7 @@ class JavascriptNativeProcessor {
     }
 
     private Variable addString(String str) {
-        Variable var = program.createVariable();
+        Variable var = program.createVariable(null);
         StringConstantInstruction nameInsn = new StringConstantInstruction();
         nameInsn.setReceiver(var);
         nameInsn.setConstant(str);
@@ -261,7 +261,7 @@ class JavascriptNativeProcessor {
             } else if (className.equals("java.lang.String")) {
                 return unwrap(var, "unwrapString", ValueType.object("java.lang.String"));
             } else {
-                Variable result = program.createVariable();
+                Variable result = program.createVariable(null);
                 CastInstruction castInsn = new CastInstruction();
                 castInsn.setReceiver(result);
                 castInsn.setValue(var);
@@ -274,7 +274,7 @@ class JavascriptNativeProcessor {
     }
 
     private Variable unwrap(Variable var, String methodName, ValueType resultType) {
-        Variable result = program.createVariable();
+        Variable result = program.createVariable(null);
         InvokeInstruction insn = new InvokeInstruction();
         insn.setMethod(new MethodReference(JS.class.getName(), methodName, ValueType.object(JSObject.class.getName()),
                 resultType));
@@ -301,7 +301,7 @@ class JavascriptNativeProcessor {
             throw new RuntimeException("Wrong functor: " + type.getName());
         }
         String name = type.getMethods().iterator().next().getName();
-        Variable functor = program.createVariable();
+        Variable functor = program.createVariable(null);
         Variable nameVar = addStringWrap(addString(name));
         InvokeInstruction insn = new InvokeInstruction();
         insn.setMethod(new MethodReference(JS.class.getName(), "function",
@@ -321,7 +321,7 @@ class JavascriptNativeProcessor {
                 return var;
             }
         }
-        Variable result = program.createVariable();
+        Variable result = program.createVariable(null);
         InvokeInstruction insn = new InvokeInstruction();
         insn.setMethod(new MethodReference(JS.class.getName(), "wrap", type,
                 ValueType.object(JSObject.class.getName())));
diff --git a/teavm-platform/src/main/java/org/teavm/platform/plugin/ResourceProgramTransformer.java b/teavm-platform/src/main/java/org/teavm/platform/plugin/ResourceProgramTransformer.java
index 6d71fb628..42070e4a8 100644
--- a/teavm-platform/src/main/java/org/teavm/platform/plugin/ResourceProgramTransformer.java
+++ b/teavm-platform/src/main/java/org/teavm/platform/plugin/ResourceProgramTransformer.java
@@ -131,7 +131,7 @@ class ResourceProgramTransformer {
         } else if (type instanceof ValueType.Object) {
             switch (((ValueType.Object)type).getClassName()) {
                 case "java.lang.String": {
-                    Variable resultVar = insn.getProgram().createVariable();
+                    Variable resultVar = insn.getProgram().createVariable(null);
                     getProperty(insn, property, instructions, resultVar);
                     InvokeInstruction castInvoke = new InvokeInstruction();
                     castInvoke.setType(InvocationType.SPECIAL);
@@ -143,7 +143,7 @@ class ResourceProgramTransformer {
                     return instructions;
                 }
                 default: {
-                    Variable resultVar = insn.getProgram().createVariable();
+                    Variable resultVar = insn.getProgram().createVariable(null);
                     getProperty(insn, property, instructions, resultVar);
                     CastInstruction castInsn = new CastInstruction();
                     castInsn.setReceiver(insn.getReceiver());
@@ -159,7 +159,7 @@ class ResourceProgramTransformer {
 
     private void getProperty(InvokeInstruction insn, String property, List<Instruction> instructions,
             Variable resultVar) {
-        Variable nameVar = program.createVariable();
+        Variable nameVar = program.createVariable(null);
         StringConstantInstruction nameInsn = new StringConstantInstruction();
         nameInsn.setConstant(property);
         nameInsn.setReceiver(nameVar);
@@ -176,7 +176,7 @@ class ResourceProgramTransformer {
 
     private void getAndCastProperty(InvokeInstruction insn, String property, List<Instruction> instructions,
             Class<?> primitive) {
-        Variable resultVar = program.createVariable();
+        Variable resultVar = program.createVariable(null);
         getProperty(insn, property, instructions, resultVar);
         InvokeInstruction castInvoke = new InvokeInstruction();
         castInvoke.setType(InvocationType.SPECIAL);
@@ -220,7 +220,7 @@ class ResourceProgramTransformer {
         } else if (type instanceof ValueType.Object) {
             switch (((ValueType.Object)type).getClassName()) {
                 case "java.lang.String": {
-                    Variable castVar = insn.getProgram().createVariable();
+                    Variable castVar = insn.getProgram().createVariable(null);
                     InvokeInstruction castInvoke = new InvokeInstruction();
                     castInvoke.setType(InvocationType.SPECIAL);
                     castInvoke.setMethod(new MethodReference(ResourceAccessor.class, "castFromString",
@@ -242,7 +242,7 @@ class ResourceProgramTransformer {
 
     private void setProperty(InvokeInstruction insn, String property, List<Instruction> instructions,
             Variable valueVar) {
-        Variable nameVar = program.createVariable();
+        Variable nameVar = program.createVariable(null);
         StringConstantInstruction nameInsn = new StringConstantInstruction();
         nameInsn.setConstant(property);
         nameInsn.setReceiver(nameVar);
@@ -259,7 +259,7 @@ class ResourceProgramTransformer {
 
     private void castAndSetProperty(InvokeInstruction insn, String property, List<Instruction> instructions,
             Class<?> primitive) {
-        Variable castVar = program.createVariable();
+        Variable castVar = program.createVariable(null);
         InvokeInstruction castInvoke = new InvokeInstruction();
         castInvoke.setType(InvocationType.SPECIAL);
         String primitiveCapitalized = primitive.getName();