C: add option to strip off information about call site locations.

This decreases executable size significantly. However, this produces
obfuscated stack traces which can be deobfuscated using JSON symbol table.

classlib/src/main/java/org/teavm/classlib/java/lang/TThrowable.java

@@ -111,10 +111,7 @@ public class TThrowable extends RuntimeException {
 
     @Unmanaged
     private static TStackTraceElement[] fillInStackTraceLowLevel() {
-        int stackSize = ExceptionHandling.callStackSize();
+        return (TStackTraceElement[]) (Object) ExceptionHandling.fillStackTrace();
-        TStackTraceElement[] stackTrace = new TStackTraceElement[stackSize];
-        ExceptionHandling.fillStackTrace((StackTraceElement[]) (Object) stackTrace);
-        return stackTrace;
     }
 
     @Rename("getMessage")

core/src/main/java/org/teavm/backend/c/CTarget.java

@@ -18,6 +18,10 @@ package org.teavm.backend.c;
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -78,6 +82,7 @@ import org.teavm.backend.lowlevel.transform.CoroutineTransformation;
 import org.teavm.backend.lowlevel.transform.WeakReferenceTransformation;
 import org.teavm.cache.EmptyMethodNodeCache;
 import org.teavm.cache.MethodNodeCache;
+import org.teavm.common.JsonUtil;
 import org.teavm.dependency.ClassDependency;
 import org.teavm.dependency.DependencyAnalyzer;
 import org.teavm.dependency.DependencyListener;
@@ -169,6 +174,7 @@ public class CTarget implements TeaVMTarget, TeaVMCHost {
     private SimpleStringPool stringPool;
     private boolean longjmpUsed = true;
     private boolean heapDump;
+    private boolean obfuscated;
     private List<CallSiteDescriptor> callSites = new ArrayList<>();
 
     public CTarget(NameProvider nameProvider) {
@@ -203,6 +209,10 @@ public class CTarget implements TeaVMTarget, TeaVMCHost {
         this.astCache = astCache;
     }
 
+    public void setObfuscated(boolean obfuscated) {
+        this.obfuscated = obfuscated;
+    }
+
     @Override
     public List<ClassHolderTransformer> getTransformers() {
         List<ClassHolderTransformer> transformers = new ArrayList<>();
@@ -392,7 +402,7 @@ public class CTarget implements TeaVMTarget, TeaVMCHost {
                 controller.getDependencyInfo(), stringPool, nameProvider, controller.getDiagnostics(), classes,
                 intrinsics, generators, asyncMethods::contains, buildTarget,
                 controller.getClassInitializerInfo(), incremental, longjmpUsed,
-                vmAssertions, vmAssertions || heapDump);
+                vmAssertions, vmAssertions || heapDump, obfuscated);
 
         BufferedCodeWriter specialWriter = new BufferedCodeWriter(false);
         BufferedCodeWriter configHeaderWriter = new BufferedCodeWriter(false);
@@ -410,6 +420,9 @@ public class CTarget implements TeaVMTarget, TeaVMCHost {
         if (heapDump) {
             configHeaderWriter.println("#define TEAVM_HEAP_DUMP 1");
         }
+        if (obfuscated) {
+            configHeaderWriter.println("#define TEAVM_OBFUSCATED 1");
+        }
 
         ClassGenerator classGenerator = new ClassGenerator(context, tagRegistry, decompiler,
                 controller.getCacheStatus());
@@ -522,6 +535,61 @@ public class CTarget implements TeaVMTarget, TeaVMCHost {
                 ? this.callSites
                 : CallSiteDescriptor.extract(context.getClassSource(), classNames);
         new CallSiteGenerator(context, writer, includes, "teavm_callSites").generate(callSites);
+        if (obfuscated) {
+            generateCallSitesJson(context.getBuildTarget(), callSites);
+        }
+    }
+
+    private void generateCallSitesJson(BuildTarget buildTarget, List<? extends CallSiteDescriptor> callSites) {
+        try (OutputStream output = buildTarget.createResource("callsites.json");
+                Writer writer = new OutputStreamWriter(output, StandardCharsets.UTF_8)) {
+            writer.append("[\n");
+            boolean first = true;
+            for (CallSiteDescriptor descriptor : callSites) {
+                if (!first) {
+                    writer.append(",\n");
+                }
+                first = false;
+                writer.append("{\"id\":").append(Integer.toString(descriptor.getId()));
+                writer.append(",\"locations\":[");
+                org.teavm.model.lowlevel.CallSiteLocation[] locations = descriptor.getLocations();
+                if (locations != null) {
+                    boolean firstLocation = true;
+                    for (org.teavm.model.lowlevel.CallSiteLocation location : locations) {
+                        if (!firstLocation) {
+                            writer.append(",");
+                        }
+                        firstLocation = false;
+                        writer.append("{\"class\":");
+                        appendJsonString(writer, location.getClassName());
+                        writer.append(",\"method\":");
+                        appendJsonString(writer, location.getMethodName());
+                        writer.append(",\"file\":");
+                        appendJsonString(writer, location.getFileName());
+                        writer.append(",\"line\":").append(Integer.toString(location.getLineNumber()));
+                        writer.append("}");
+                    }
+                }
+                writer.append("]}");
+            }
+            if (!first) {
+                writer.append("\n");
+            }
+            writer.append("]");
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private static void appendJsonString(Writer writer, String string) throws IOException {
+        if (string == null) {
+            writer.append("null");
+            return;
+        }
+
+        writer.append("\"");
+        JsonUtil.writeEscapedString(writer, string);
+        writer.append("\"");
     }
 
     private void generateStrings(BuildTarget buildTarget, GenerationContext context) throws IOException {

core/src/main/java/org/teavm/backend/c/generate/CallSiteGenerator.java

@@ -26,7 +26,6 @@ import org.teavm.model.lowlevel.CallSiteLocation;
 import org.teavm.model.lowlevel.ExceptionHandlerDescriptor;
 
 public class CallSiteGenerator {
-
     private GenerationContext context;
     private CodeWriter writer;
     private IncludeManager includes;
@@ -79,6 +78,7 @@ public class CallSiteGenerator {
             first = false;
 
             int locationIndex = -1;
+            if (!context.isObfuscated()) {
                 CallSiteLocation[] locations = callSite.getLocations();
                 if (locations != null && locations.length > 0) {
                     LocationList prevList = null;
@@ -95,6 +95,7 @@ public class CallSiteGenerator {
                         prevList = list;
                     }
                 }
+            }
 
             String firstHandlerExpr = !callSite.getHandlers().isEmpty()
                     ? "exceptionHandlers_" + callSitesName + " + " + exceptionHandlers.size()

core/src/main/java/org/teavm/backend/c/generate/GenerationContext.java

@@ -50,13 +50,14 @@ public class GenerationContext {
     private boolean longjmp;
     private boolean vmAssertions;
     private boolean heapDump;
+    private boolean obfuscated;
 
     public GenerationContext(VirtualTableProvider virtualTableProvider, Characteristics characteristics,
             DependencyInfo dependencies, StringPool stringPool, NameProvider names, Diagnostics diagnostics,
             ClassReaderSource classSource, List<Intrinsic> intrinsics, List<Generator> generators,
             Predicate<MethodReference> asyncMethods, BuildTarget buildTarget,
             ClassInitializerInfo classInitializerInfo, boolean incremental, boolean longjmp, boolean vmAssertions,
-            boolean heapDump) {
+            boolean heapDump, boolean obfuscated) {
         this.virtualTableProvider = virtualTableProvider;
         this.characteristics = characteristics;
         this.dependencies = dependencies;
@@ -73,6 +74,7 @@ public class GenerationContext {
         this.longjmp = longjmp;
         this.vmAssertions = vmAssertions;
         this.heapDump = heapDump;
+        this.obfuscated = obfuscated;
     }
 
     public void addIntrinsic(Intrinsic intrinsic) {
@@ -152,4 +154,8 @@ public class GenerationContext {
     public boolean isVmAssertions() {
         return vmAssertions;
     }
+
+    public boolean isObfuscated() {
+        return obfuscated;
+    }
 }

core/src/main/java/org/teavm/backend/c/intrinsic/ExceptionHandlingIntrinsic.java

@@ -31,6 +31,7 @@ public class ExceptionHandlingIntrinsic implements Intrinsic {
             case "isJumpSupported":
             case "jumpToFrame":
             case "abort":
+            case "isObfuscated":
                 return true;
             default:
                 return false;
@@ -64,6 +65,10 @@ public class ExceptionHandlingIntrinsic implements Intrinsic {
                 context.includes().addInclude("<stdlib.h>");
                 context.writer().print("abort();");
                 break;
+
+            case "isObfuscated":
+                context.writer().print("TEAVM_OBFUSCATED");
+                break;
         }
     }
 }

core/src/main/java/org/teavm/backend/wasm/intrinsics/ExceptionHandlingIntrinsic.java

@@ -54,6 +54,7 @@ public class ExceptionHandlingIntrinsic implements WasmIntrinsic {
             case "isJumpSupported":
             case "jumpToFrame":
             case "abort":
+            case "isObfuscated":
                 return true;
         }
         return false;
@@ -83,6 +84,7 @@ public class ExceptionHandlingIntrinsic implements WasmIntrinsic {
             }
 
             case "isJumpSupported":
+            case "isObfuscated":
                 return new WasmInt32Constant(0);
 
             case "jumpToFrame":

core/src/main/java/org/teavm/common/JsonUtil.java

@@ -0,0 +1,53 @@
+/*
+ *  Copyright 2019 konsoletyper.
+ *
+ *  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.common;
+
+import java.io.IOException;
+import java.io.Writer;
+
+public final class JsonUtil {
+    private JsonUtil() {
+    }
+
+    public static void writeEscapedString(Writer output, String str) throws IOException {
+        for (int i = 0; i < str.length(); ++i) {
+            char c = str.charAt(i);
+            switch (c) {
+                case '\n':
+                    output.write("\\n");
+                    break;
+                case '\r':
+                    output.write("\\r");
+                    break;
+                case '\t':
+                    output.write("\\t");
+                    break;
+                case '\b':
+                    output.write("\\b");
+                    break;
+                case '\\':
+                    output.write("\\\\");
+                    break;
+                case '"':
+                    output.write("\\\"");
+                    break;
+                default:
+                    output.write(c);
+                    break;
+            }
+        }
+    }
+}

core/src/main/java/org/teavm/debugging/information/SourceMapsWriter.java

@@ -17,6 +17,7 @@ package org.teavm.debugging.information;
 
 import java.io.IOException;
 import java.io.Writer;
+import org.teavm.common.JsonUtil;
 
 class SourceMapsWriter {
     private static final String BASE64_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
@@ -34,10 +35,10 @@ class SourceMapsWriter {
     public void write(String generatedFile, String sourceRoot, DebugInformation debugInfo) throws IOException {
         output.write("{\"version\":3");
         output.write(",\"file\":\"");
-        writeEscapedString(generatedFile);
+        JsonUtil.writeEscapedString(output, generatedFile);
         output.write("\"");
         output.write(",\"sourceRoot\":\"");
-        writeEscapedString(sourceRoot);
+        JsonUtil.writeEscapedString(output, sourceRoot);
         output.write("\"");
         output.write(",\"sources\":[");
         for (int i = 0; i < debugInfo.fileNames.length; ++i) {
@@ -45,7 +46,7 @@ class SourceMapsWriter {
                 output.write(',');
             }
             output.write("\"");
-            writeEscapedString(debugInfo.fileNames[i]);
+            JsonUtil.writeEscapedString(output, debugInfo.fileNames[i]);
             output.write("\"");
         }
         output.write("]");
@@ -85,35 +86,6 @@ class SourceMapsWriter {
         first = false;
     }
 
-    private void writeEscapedString(String str) throws IOException {
-        for (int i = 0; i < str.length(); ++i) {
-            char c = str.charAt(i);
-            switch (c) {
-                case '\n':
-                    output.write("\\n");
-                    break;
-                case '\r':
-                    output.write("\\r");
-                    break;
-                case '\t':
-                    output.write("\\t");
-                    break;
-                case '\b':
-                    output.write("\\b");
-                    break;
-                case '\\':
-                    output.write("\\\\");
-                    break;
-                case '"':
-                    output.write("\\\"");
-                    break;
-                default:
-                    output.write(c);
-                    break;
-            }
-        }
-    }
-
     private void writeVLQ(int number) throws IOException {
         if (number < 0) {
             number = ((-number) << 1) | 1;

core/src/main/java/org/teavm/runtime/ExceptionHandling.java

@@ -37,11 +37,19 @@ public final class ExceptionHandling {
     @Unmanaged
     public static native void abort();
 
+    @Unmanaged
+    private static native boolean isObfuscated();
+
     @Unmanaged
     public static void printStack() {
         Address stackFrame = ShadowStack.getStackTop();
         while (stackFrame != null) {
             int callSiteId = ShadowStack.getCallSiteId(stackFrame);
+            if (isObfuscated()) {
+                Console.printString("    at Obfuscated.obfuscated(Obfuscated.java:");
+                Console.printInt(callSiteId);
+                Console.printString(")\n");
+            } else {
                 CallSite callSite = findCallSiteById(callSiteId, stackFrame);
                 CallSiteLocation location = callSite.location;
                 while (location != null) {
@@ -65,6 +73,7 @@ public final class ExceptionHandling {
 
                     location = location.next;
                 }
+            }
             stackFrame = ShadowStack.getNextStackFrame(stackFrame);
         }
     }
@@ -137,14 +146,14 @@ public final class ExceptionHandling {
     }
 
     @Unmanaged
-    public static int callStackSize() {
+    private static int callStackSize() {
         Address stackFrame = ShadowStack.getStackTop();
         int size = 0;
         while (stackFrame != null) {
             int callSiteId = ShadowStack.getCallSiteId(stackFrame);
             CallSite callSite = findCallSiteById(callSiteId, stackFrame);
             CallSiteLocation location = callSite.location;
-            if (location == null) {
+            if (isObfuscated() || location == null) {
                 size++;
             } else {
                 while (location != null) {
@@ -159,27 +168,35 @@ public final class ExceptionHandling {
     }
 
     @Unmanaged
-    public static void fillStackTrace(StackTraceElement[] target) {
+    public static StackTraceElement[] fillStackTrace() {
         Address stackFrame = ShadowStack.getStackTop();
+        int size = callStackSize();
+
+        ShadowStack.allocStack(1);
+        StackTraceElement[] target = new StackTraceElement[size];
+        ShadowStack.registerGCRoot(0, target);
+
         int index = 0;
         while (stackFrame != null) {
             int callSiteId = ShadowStack.getCallSiteId(stackFrame);
             CallSite callSite = findCallSiteById(callSiteId, stackFrame);
             CallSiteLocation location = callSite.location;
-            if (location == null) {
+            if (isObfuscated()) {
-                target[index++] = createElement("", "", null, location.lineNumber);
+                target[index++] = new StackTraceElement("Obfuscated", "obfuscated", "Obfuscated.java", callSiteId);
+            } else if (location == null) {
+                target[index++] = new StackTraceElement("", "", null, location.lineNumber);
             } else {
                 while (location != null) {
                     MethodLocation methodLocation = location.method;
                     StackTraceElement element;
                     if (methodLocation != null) {
-                        element = createElement(
+                        element = new StackTraceElement(
                                 methodLocation.className != null ? methodLocation.className.value : "",
                                 methodLocation.methodName != null ? methodLocation.methodName.value : "",
                                 methodLocation.fileName != null ? methodLocation.fileName.value : null,
                                 location.lineNumber);
                     } else {
-                        element = createElement("", "", null, location.lineNumber);
+                        element = new StackTraceElement("", "", null, location.lineNumber);
                     }
                     target[index++] = element;
                     location = location.next;
@@ -187,10 +204,8 @@ public final class ExceptionHandling {
             }
             stackFrame = ShadowStack.getNextStackFrame(stackFrame);
         }
-    }
+        ShadowStack.releaseStack(1);
 
-    private static StackTraceElement createElement(String className, String methodName, String fileName,
+        return target;
-            int lineNumber) {
-        return new StackTraceElement(className, methodName, fileName, lineNumber);
     }
 }

core/src/main/resources/org/teavm/backend/c/definitions.h

@@ -58,3 +58,7 @@
 #ifndef TEAVM_GC_LOG
     #define TEAVM_GC_LOG 0
 #endif
+
+#ifndef TEAVM_OBFUSCATED
+    #define TEAVM_OBFUSCATED 0
+#endif

tools/core/src/main/java/org/teavm/tooling/TeaVMTool.java

@@ -342,6 +342,7 @@ public class TeaVMTool {
         cTarget.setLineNumbersGenerated(debugInformationGenerated);
         cTarget.setLongjmpUsed(longjmpSupported);
         cTarget.setHeapDump(heapDump);
+        cTarget.setObfuscated(minifying);
         return cTarget;
     }