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 c421957e6..d0b1cbf37 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
@@ -6,6 +6,8 @@ import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.*;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 import org.codehaus.jackson.JsonNode;
 import org.codehaus.jackson.map.ObjectMapper;
 import org.teavm.chromerdp.data.*;
@@ -20,6 +22,7 @@ public class ChromeRDPDebugger implements JavaScriptDebugger, ChromeRDPExchangeC
     private static final Object dummy = new Object();
     private ChromeRDPExchange exchange;
     private ConcurrentMap<JavaScriptDebuggerListener, Object> listeners = new ConcurrentHashMap<>();
+    private ConcurrentMap<JavaScriptLocation, RDPBreakpoint> breakpointLocationMap = new ConcurrentHashMap<>();
     private ConcurrentMap<RDPBreakpoint, Object> breakpoints = new ConcurrentHashMap<>();
     private volatile RDPCallFrame[] callStack = new RDPCallFrame[0];
     private ConcurrentMap<String, String> scripts = new ConcurrentHashMap<>();
@@ -28,6 +31,7 @@ public class ChromeRDPDebugger implements JavaScriptDebugger, ChromeRDPExchangeC
     private ObjectMapper mapper = new ObjectMapper();
     private ConcurrentMap<Integer, ResponseHandler> responseHandlers = new ConcurrentHashMap<>();
     private AtomicInteger messageIdGenerator = new AtomicInteger();
+    private Lock breakpointLock = new ReentrantLock();
 
     private List<JavaScriptDebuggerListener> getListeners() {
         return new ArrayList<>(listeners.keySet());
@@ -74,7 +78,7 @@ public class ChromeRDPDebugger implements JavaScriptDebugger, ChromeRDPExchangeC
                     if (jsonMessage.has("id")) {
                         Response response = mapper.reader(Response.class).readValue(jsonMessage);
                         if (response.getError() != null) {
-                            System.err.println(response.getError().toString());
+                            System.err.println("#" + jsonMessage.get("id") + ": " + response.getError().toString());
                         }
                         responseHandlers.remove(response.getId()).received(response.getResult());
                     } else {
@@ -235,21 +239,49 @@ public class ChromeRDPDebugger implements JavaScriptDebugger, ChromeRDPExchangeC
 
     @Override
     public JavaScriptBreakpoint createBreakpoint(JavaScriptLocation location) {
-        RDPBreakpoint breakpoint = new RDPBreakpoint(this, location);
-        breakpoints.put(breakpoint, dummy);
-        updateBreakpoint(breakpoint);
+        RDPBreakpoint breakpoint;
+
+        breakpointLock.lock();
+        try {
+            breakpoint = breakpointLocationMap.get(location);
+            if (breakpoint == null) {
+                breakpoint = new RDPBreakpoint(this, location);
+                breakpointLocationMap.put(location, breakpoint);
+                updateBreakpoint(breakpoint);
+            }
+            breakpoint.referenceCount.incrementAndGet();
+            breakpoints.put(breakpoint, dummy);
+        } finally {
+            breakpointLock.unlock();
+        }
+
         return breakpoint;
     }
 
     void destroyBreakpoint(RDPBreakpoint breakpoint) {
-        breakpoints.remove(breakpoint);
-        if (breakpoint.chromeId != null) {
-            Message message = new Message();
-            message.setMethod("Debugger.removeBreakpoint");
-            RemoveBreakpointCommand params = new RemoveBreakpointCommand();
-            params.setBreakpointId(breakpoint.chromeId);
-            message.setParams(mapper.valueToTree(params));
-            sendMessage(message);
+        if (breakpoint.referenceCount.decrementAndGet() > 0) {
+            return;
+        }
+        breakpointLock.lock();
+        try {
+            if (breakpoint.referenceCount.get() > 0) {
+                return;
+            }
+            breakpointLocationMap.remove(breakpoint.getLocation());
+            breakpoints.remove(breakpoint);
+            if (breakpoint.chromeId != null) {
+                System.out.println("Removing breakpoint at " + breakpoint.getLocation());
+                Message message = new Message();
+                message.setMethod("Debugger.removeBreakpoint");
+                RemoveBreakpointCommand params = new RemoveBreakpointCommand();
+                params.setBreakpointId(breakpoint.chromeId);
+                message.setParams(mapper.valueToTree(params));
+                sendMessage(message);
+            }
+            breakpoint.debugger = null;
+            breakpoint.chromeId = null;
+        } finally {
+            breakpointLock.unlock();
         }
     }
 
@@ -260,21 +292,24 @@ public class ChromeRDPDebugger implements JavaScriptDebugger, ChromeRDPExchangeC
     }
 
     void updateBreakpoint(final RDPBreakpoint breakpoint) {
-        if (exchange == null) {
+        if (exchange == null || breakpoint.chromeId != null) {
             return;
         }
-        Message message = new Message();
+        final Message message = new Message();
         message.setId(messageIdGenerator.incrementAndGet());
         message.setMethod("Debugger.setBreakpoint");
         SetBreakpointCommand params = new SetBreakpointCommand();
         params.setLocation(unmap(breakpoint.getLocation()));
         message.setParams(mapper.valueToTree(params));
+        System.out.println("Setting breakpoint at: " + breakpoint.getLocation());
         ResponseHandler handler = new ResponseHandler() {
             @Override public void received(JsonNode node) throws IOException {
                 if (node != null) {
                     SetBreakpointResponse response = mapper.reader(SetBreakpointResponse.class).readValue(node);
                     breakpoint.chromeId = response.getBreakpointId();
                 } else {
+                    System.err.println("Error setting breakpoint at " + breakpoint.getLocation() +
+                            ", message id is " + message.getId());
                     breakpoint.chromeId = null;
                 }
                 for (JavaScriptDebuggerListener listener : getListeners()) {
diff --git a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPBreakpoint.java b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPBreakpoint.java
index 08411fd65..278400419 100644
--- a/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPBreakpoint.java
+++ b/teavm-chrome-rdp/src/main/java/org/teavm/chromerdp/RDPBreakpoint.java
@@ -15,6 +15,7 @@
  */
 package org.teavm.chromerdp;
 
+import java.util.concurrent.atomic.AtomicInteger;
 import org.teavm.debugging.JavaScriptBreakpoint;
 import org.teavm.debugging.JavaScriptLocation;
 
@@ -24,8 +25,9 @@ import org.teavm.debugging.JavaScriptLocation;
  */
 public class RDPBreakpoint implements JavaScriptBreakpoint {
     volatile String chromeId;
-    private ChromeRDPDebugger debugger;
+    ChromeRDPDebugger debugger;
     private JavaScriptLocation location;
+    AtomicInteger referenceCount = new AtomicInteger();
 
     RDPBreakpoint(ChromeRDPDebugger debugger, JavaScriptLocation location) {
         this.debugger = debugger;
@@ -41,8 +43,6 @@ public class RDPBreakpoint implements JavaScriptBreakpoint {
     public void destroy() {
         if (debugger != null) {
             debugger.destroyBreakpoint(this);
-            chromeId = null;
-            debugger = null;
         }
     }
 
diff --git a/teavm-core/src/main/java/org/teavm/debugging/Breakpoint.java b/teavm-core/src/main/java/org/teavm/debugging/Breakpoint.java
index baf995aa8..4bcc22135 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/Breakpoint.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/Breakpoint.java
@@ -46,7 +46,7 @@ public class Breakpoint {
         return valid;
     }
 
-    public synchronized boolean isDestroyed() {
+    public boolean isDestroyed() {
         return debugger == null;
     }
 
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 b75fe157a..8d9e914c9 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/DebugInformation.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/DebugInformation.java
@@ -61,7 +61,7 @@ public class DebugInformation {
         if (description == null) {
             return Collections.emptyList();
         }
-        if (line > description.generatedLocationStart.length) {
+        if (line >= description.generatedLocationStart.length - 1) {
             return Collections.emptyList();
         }
         int start = description.generatedLocationStart[line];
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 ee79b31b4..743ec5514 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/DebugInformationBuilder.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/DebugInformationBuilder.java
@@ -136,9 +136,9 @@ public class DebugInformationBuilder implements DebugInformationEmitter {
         }
         for (SourceLocation succ : successors) {
             if (succ == null) {
-                cfg.add(location.getLine(), fileIndex, -1);
+                cfg.add(location.getLine(), -1, fileIndex);
             } else {
-                cfg.add(location.getLine(), files.index(succ.getFileName()), succ.getLine());
+                cfg.add(location.getLine(), succ.getLine(), files.index(succ.getFileName()));
             }
         }
     }
@@ -183,6 +183,7 @@ public class DebugInformationBuilder implements DebugInformationEmitter {
                     cfgs[i] = this.cfgs.get(i).build();
                 }
             }
+            debugInformation.controlFlowGraphs = cfgs;
 
             debugInformation.rebuildFileDescriptions();
             debugInformation.rebuildMaps();
@@ -354,7 +355,7 @@ public class DebugInformationBuilder implements DebugInformationEmitter {
                 }
                 long[] pairs = new long[linesChunk.size()];
                 for (int j = 0; j < pairs.length; ++j) {
-                    pairs[j] = (filesChunk.get(j) << 32) | linesChunk.get(j);
+                    pairs[j] = (((long)filesChunk.get(j)) << 32) | linesChunk.get(j);
                 }
                 Arrays.sort(pairs);
                 int distinctSize = 0;
@@ -362,16 +363,16 @@ public class DebugInformationBuilder implements DebugInformationEmitter {
                     long pair = pairs[j];
                     if (distinctSize == 0 || pair != pairs[distinctSize]) {
                         pairs[distinctSize++] = pair;
-                        linesData.add((int)(pair >>> 32));
-                        filesData.add((int)pair);
+                        filesData.add((int)(pair >>> 32));
+                        linesData.add((int)pair);
                     }
                 }
                 offsets[i + 1] = linesData.size();
             }
             DebugInformation.CFG cfg = new DebugInformation.CFG();
             cfg.offsets = offsets;
-            cfg.lines = lines.getAll();
-            cfg.files = files.getAll();
+            cfg.lines = linesData.getAll();
+            cfg.files = filesData.getAll();
             return cfg;
         }
     }
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 21d72ab30..dcb5ef39d 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/Debugger.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/Debugger.java
@@ -54,24 +54,62 @@ public class Debugger {
         listeners.remove(listener);
     }
 
-    public synchronized void suspend() {
+    public void suspend() {
         javaScriptDebugger.suspend();
     }
 
-    public synchronized void resume() {
+    public void resume() {
         javaScriptDebugger.resume();
     }
 
-    public synchronized void stepInto() {
+    public void stepInto() {
         javaScriptDebugger.stepInto();
     }
 
-    public synchronized void stepOut() {
+    public void stepOut() {
         javaScriptDebugger.stepOut();
     }
 
-    public synchronized void stepOver() {
-        javaScriptDebugger.stepOver();
+    public void stepOver() {
+        CallFrame[] callStack = getCallStack();
+        if (callStack == null || callStack.length == 0) {
+            javaScriptDebugger.stepOver();
+            return;
+        }
+        CallFrame recentFrame = callStack[0];
+        if (recentFrame.getLocation() == null || recentFrame.getLocation().getFileName() == null ||
+                recentFrame.getLocation().getLine() < 0) {
+            javaScriptDebugger.stepOver();
+            return;
+        }
+        Set<JavaScriptLocation> successors = new HashSet<>();
+        for (int i = 0; i < callStack.length; ++i) {
+            CallFrame frame = callStack[i];
+            boolean exits = false;
+            for (Map.Entry<String, DebugInformation> entry : debugInformationMap.entrySet()) {
+                DebugInformation debugInfo = entry.getValue();
+                SourceLocation[] following = debugInfo.getFollowingLines(frame.getLocation());
+                if (following == null) {
+                    continue;
+                }
+                for (SourceLocation successor : debugInfo.getFollowingLines(frame.getLocation())) {
+                    if (successor == null) {
+                        exits = true;
+                    } else {
+                        for (GeneratedLocation loc : debugInfo.getGeneratedLocations(successor)) {
+                            successors.add(new JavaScriptLocation(entry.getKey(), loc.getLine(), loc.getColumn()));
+                        }
+                    }
+                }
+            }
+            if (!exits) {
+                break;
+            }
+        }
+        for (JavaScriptLocation successor : successors) {
+            temporaryBreakpoints.add(javaScriptDebugger.createBreakpoint(successor));
+        }
+        javaScriptDebugger.resume();
     }
 
     private List<DebugInformation> debugInformationBySource(String sourceFile) {
@@ -249,8 +287,8 @@ public class Debugger {
     }
 
     private void fireResumed() {
-        List<JavaScriptBreakpoint> termporaryBreakpoints = new ArrayList<>();
-        this.temporaryBreakpoints.drainTo(termporaryBreakpoints);
+        List<JavaScriptBreakpoint> temporaryBreakpoints = new ArrayList<>();
+        this.temporaryBreakpoints.drainTo(temporaryBreakpoints);
         for (JavaScriptBreakpoint jsBreakpoint : temporaryBreakpoints) {
             jsBreakpoint.destroy();
         }
diff --git a/teavm-core/src/main/java/org/teavm/debugging/JavaScriptLocation.java b/teavm-core/src/main/java/org/teavm/debugging/JavaScriptLocation.java
index 64d6372fc..0bb830ac3 100644
--- a/teavm-core/src/main/java/org/teavm/debugging/JavaScriptLocation.java
+++ b/teavm-core/src/main/java/org/teavm/debugging/JavaScriptLocation.java
@@ -15,6 +15,8 @@
  */
 package org.teavm.debugging;
 
+import java.util.Objects;
+
 /**
  *
  * @author Alexey Andreev
@@ -42,6 +44,23 @@ public class JavaScriptLocation {
         return column;
     }
 
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (!(obj instanceof JavaScriptLocation)) {
+            return false;
+        }
+        JavaScriptLocation other = (JavaScriptLocation)obj;
+        return Objects.equals(other.script, script) && other.line == line;
+    }
+
+    @Override
+    public int hashCode() {
+        return (31 + line) * 31 + Objects.hashCode(script);
+    }
+
     @Override
     public String toString() {
         return script + ":(" + line + ";" + column + ")";
diff --git a/teavm-core/src/main/java/org/teavm/model/InstructionLocation.java b/teavm-core/src/main/java/org/teavm/model/InstructionLocation.java
index 40bee89cb..eb6a92898 100644
--- a/teavm-core/src/main/java/org/teavm/model/InstructionLocation.java
+++ b/teavm-core/src/main/java/org/teavm/model/InstructionLocation.java
@@ -58,4 +58,9 @@ public class InstructionLocation {
         InstructionLocation other = (InstructionLocation)obj;
         return Objects.equals(fileName, other.fileName) && line == other.line;
     }
+
+    @Override
+    public String toString() {
+        return fileName + ":" + line;
+    }
 }
diff --git a/teavm-core/src/main/java/org/teavm/model/util/LocationGraphBuilder.java b/teavm-core/src/main/java/org/teavm/model/util/LocationGraphBuilder.java
new file mode 100644
index 000000000..3179fafdf
--- /dev/null
+++ b/teavm-core/src/main/java/org/teavm/model/util/LocationGraphBuilder.java
@@ -0,0 +1,139 @@
+/*
+ *  Copyright 2014 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.model.util;
+
+import java.util.*;
+import org.teavm.common.Graph;
+import org.teavm.model.BasicBlock;
+import org.teavm.model.Instruction;
+import org.teavm.model.InstructionLocation;
+import org.teavm.model.Program;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+class LocationGraphBuilder {
+    private Map<InstructionLocation, Set<InstructionLocation>> graphBuilder;
+    private List<Set<InstructionLocation>> startLocations;
+    private List<AdditionalConnection> additionalConnections;
+
+    public Map<InstructionLocation, InstructionLocation[]> build(Program program) {
+        graphBuilder = new HashMap<>();
+        Graph graph = ProgramUtils.buildControlFlowGraph(program);
+        dfs(graph, program);
+        return assemble();
+    }
+
+    private void dfs(Graph graph, Program program) {
+        startLocations = new ArrayList<>(Collections.<Set<InstructionLocation>>nCopies(graph.size(), null));
+        additionalConnections = new ArrayList<>();
+        Deque<Step> stack = new ArrayDeque<>();
+        for (int i = 0; i < graph.size(); ++i) {
+            if (graph.incomingEdgesCount(i) == 0) {
+                stack.push(new Step(null, new HashSet<InstructionLocation>(), i));
+            }
+        }
+        boolean[] visited = new boolean[graph.size()];
+        InstructionLocation[] blockLocations = new InstructionLocation[graph.size()];
+
+        while (!stack.isEmpty()) {
+            Step step = stack.pop();
+            if (visited[step.block]) {
+                if (step.location != null) {
+                    additionalConnections.add(new AdditionalConnection(step.location, startLocations.get(step.block)));
+                }
+                continue;
+            }
+            visited[step.block] = true;
+            startLocations.set(step.block, step.startLocations);
+            BasicBlock block = program.basicBlockAt(step.block);
+            InstructionLocation location = step.location;
+            boolean started = false;
+            for (Instruction insn : block.getInstructions()) {
+                if (insn.getLocation() != null) {
+                    if (!started) {
+                        step.startLocations.add(location);
+                    }
+                    started = true;
+                    if (blockLocations[step.block] == null) {
+                        blockLocations[step.block] = insn.getLocation();
+                    }
+                    if (location != null && !Objects.equals(location, insn.getLocation())) {
+                        addEdge(location, insn.getLocation());
+                    }
+                    location = insn.getLocation();
+                }
+            }
+            if (graph.outgoingEdgesCount(step.block) == 0) {
+                addEdge(location, new InstructionLocation(null, -1));
+            } else {
+                for (int next : graph.outgoingEdges(step.block)) {
+                    stack.push(new Step(location, started ? new HashSet<InstructionLocation>() : step.startLocations,
+                            next));
+                }
+            }
+        }
+    }
+
+    private Map<InstructionLocation, InstructionLocation[]> assemble() {
+        for (AdditionalConnection additionalConn : additionalConnections) {
+            for (InstructionLocation succ : additionalConn.successors) {
+                addEdge(additionalConn.location, succ);
+            }
+        }
+        Map<InstructionLocation, InstructionLocation[]> locationGraph = new HashMap<>();
+        for (Map.Entry<InstructionLocation, Set<InstructionLocation>> entry : graphBuilder.entrySet()) {
+            InstructionLocation[] successors = entry.getValue().toArray(new InstructionLocation[0]);
+            for (int i = 0; i < successors.length; ++i) {
+                if (successors[i].getLine() < 0) {
+                    successors[i] = null;
+                }
+            }
+            locationGraph.put(entry.getKey(), successors);
+        }
+        return locationGraph;
+    }
+
+    private void addEdge(InstructionLocation source, InstructionLocation dest) {
+        Set<InstructionLocation> successors = graphBuilder.get(source);
+        if (successors == null) {
+            successors = new HashSet<>();
+            graphBuilder.put(source, successors);
+        }
+        successors.add(dest);
+    }
+
+    static class Step {
+        InstructionLocation location;
+        Set<InstructionLocation> startLocations;
+        int block;
+        public Step(InstructionLocation location, Set<InstructionLocation> startLocations, int block) {
+            this.location = location;
+            this.startLocations = startLocations;
+            this.block = block;
+        }
+    }
+
+    static class AdditionalConnection {
+        InstructionLocation location;
+        Set<InstructionLocation> successors;
+        public AdditionalConnection(InstructionLocation location, Set<InstructionLocation> successors) {
+            this.location = location;
+            this.successors = successors;
+        }
+    }
+}
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 3d31047ff..6acc9c20c 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
@@ -69,64 +69,7 @@ public final class ProgramUtils {
     }
 
     public static Map<InstructionLocation, InstructionLocation[]> getLocationCFG(Program program) {
-        Graph graph = buildControlFlowGraph(program);
-        class Step {
-            InstructionLocation location;
-            int block;
-        }
-        Deque<Step> stack = new ArrayDeque<>();
-        for (int i = 0; i < graph.size(); ++i) {
-            if (graph.incomingEdgesCount(i) == 0) {
-                Step step = new Step();
-                step.block = i;
-                step.location = null;
-                stack.push(step);
-            }
-        }
-        boolean[] visited = new boolean[graph.size()];
-        Map<InstructionLocation, Set<InstructionLocation>> locationGraphBuilder = new HashMap<>();
-        while (!stack.isEmpty()) {
-            Step step = stack.pop();
-            if (visited[step.block]) {
-                continue;
-            }
-            visited[step.block] = true;
-            BasicBlock block = program.basicBlockAt(step.block);
-            InstructionLocation location = step.location;
-            for (Instruction insn : block.getInstructions()) {
-                if (insn.getLocation() != null) {
-                    if (location != null) {
-                        Set<InstructionLocation> successors = locationGraphBuilder.get(location);
-                        if (successors == null) {
-                            successors = new HashSet<>();
-                            locationGraphBuilder.put(location, successors);
-                        }
-                        successors.add(insn.getLocation());
-                    }
-                    location = insn.getLocation();
-                }
-            }
-            if (graph.outgoingEdgesCount(step.block) == 0) {
-                Set<InstructionLocation> successors = locationGraphBuilder.get(location);
-                if (successors == null) {
-                    successors = new HashSet<>();
-                    locationGraphBuilder.put(location, successors);
-                }
-                successors.add(new InstructionLocation(null, -1));
-            } else {
-                for (int next : graph.outgoingEdges(step.block)) {
-                    step = new Step();
-                    step.location = location;
-                    step.block = next;
-                    stack.push(step);
-                }
-            }
-        }
-        Map<InstructionLocation, InstructionLocation[]> locationGraph = new HashMap<>();
-        for (Map.Entry<InstructionLocation, Set<InstructionLocation>> entry : locationGraphBuilder.entrySet()) {
-            locationGraph.put(entry.getKey(), entry.getValue().toArray(new InstructionLocation[0]));
-        }
-        return locationGraph;
+        return new LocationGraphBuilder().build(program);
     }
 
     public static Program copy(ProgramReader program) {
diff --git a/teavm-core/src/main/java/org/teavm/vm/TeaVM.java b/teavm-core/src/main/java/org/teavm/vm/TeaVM.java
index e0d597275..70adbaa68 100644
--- a/teavm-core/src/main/java/org/teavm/vm/TeaVM.java
+++ b/teavm-core/src/main/java/org/teavm/vm/TeaVM.java
@@ -21,6 +21,7 @@ import org.teavm.codegen.*;
 import org.teavm.common.FiniteExecutor;
 import org.teavm.common.ServiceRepository;
 import org.teavm.debugging.DebugInformationEmitter;
+import org.teavm.debugging.SourceLocation;
 import org.teavm.dependency.*;
 import org.teavm.javascript.Decompiler;
 import org.teavm.javascript.Renderer;
@@ -349,6 +350,14 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
         SourceWriter sourceWriter = builder.build(writer);
         Renderer renderer = new Renderer(sourceWriter, classSet, classLoader, this);
         if (debugEmitter != null) {
+            for (String className : classSet.getClassNames()) {
+                ClassHolder cls = classSet.get(className);
+                for (MethodHolder method : cls.getMethods()) {
+                    if (method.getProgram() != null) {
+                        emitCFG(debugEmitter, method.getProgram());
+                    }
+                }
+            }
             renderer.setDebugEmitter(debugEmitter);
         }
         renderer.getDebugEmitter().setLocationProvider(sourceWriter);
@@ -387,6 +396,25 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
         }
     }
 
+    private void emitCFG(DebugInformationEmitter emitter, Program program) {
+        Map<InstructionLocation, InstructionLocation[]> cfg = ProgramUtils.getLocationCFG(program);
+        for (Map.Entry<InstructionLocation, InstructionLocation[]> entry : cfg.entrySet()) {
+            SourceLocation location = map(entry.getKey());
+            SourceLocation[] successors = new SourceLocation[entry.getValue().length];
+            for (int i = 0; i < entry.getValue().length; ++i) {
+                successors[i] = map(entry.getValue()[i]);
+            }
+            emitter.addSuccessors(location, successors);
+        }
+    }
+
+    private static SourceLocation map(InstructionLocation location) {
+        if (location == null) {
+            return null;
+        }
+        return new SourceLocation(location.getFileName(), location.getLine());
+    }
+
     private void devirtualize(ListableClassHolderSource classes, DependencyInfo dependency) {
         final Devirtualization devirtualization = new Devirtualization(dependency, classes);
         for (String className : classes.getClassNames()) {