Reduce minumus JS runtime a little

core/src/main/java/org/teavm/backend/javascript/JavaScriptTarget.java

@@ -100,6 +100,7 @@ public class JavaScriptTarget implements TeaVMTarget, TeaVMJavaScriptHost {
 
     private TeaVMTargetController controller;
     private boolean minifying = true;
+    private boolean stackTraceIncluded = false;
     private final Map<MethodReference, Generator> methodGenerators = new HashMap<>();
     private final Map<MethodReference, Injector> methodInjectors = new HashMap<>();
     private final List<Function<ProviderContext, Generator>> generatorProviders = new ArrayList<>();
@@ -194,6 +195,10 @@ public class JavaScriptTarget implements TeaVMTarget, TeaVMJavaScriptHost {
         return true;
     }
 
+    public void setStackTraceIncluded(boolean stackTraceIncluded) {
+        this.stackTraceIncluded = stackTraceIncluded;
+    }
+
     @Override
     public List<TeaVMHostExtension> getHostExtensions() {
         return Collections.singletonList(this);
@@ -219,7 +224,7 @@ public class JavaScriptTarget implements TeaVMTarget, TeaVMJavaScriptHost {
 
         dependencyAnalyzer.linkField(new FieldReference(String.class.getName(), "characters"), null);
 
-        dependencyAnalyzer.linkMethod(new MethodReference(Object.class, "clone", Object.class), null).use();
+        dependencyAnalyzer.linkMethod(new MethodReference(Object.class, "clone", Object.class), null);
         MethodDependency exceptionCons = dependencyAnalyzer.linkMethod(new MethodReference(
                 NoClassDefFoundError.class, "<init>", String.class, void.class), null);
 
@@ -246,6 +251,16 @@ public class JavaScriptTarget implements TeaVMTarget, TeaVMJavaScriptHost {
         exceptionCons.getVariable(1).propagate(stringType);
         exceptionCons.use();
 
+        if (stackTraceIncluded) {
+            includeStackTraceMethods(dependencyAnalyzer);
+        }
+    }
+
+    public static void includeStackTraceMethods(DependencyAnalyzer dependencyAnalyzer) {
+        MethodDependency dep;
+
+        DependencyType stringType = dependencyAnalyzer.getType("java.lang.String");
+
         dep = dependencyAnalyzer.linkMethod(new MethodReference(
                 StackTraceElement.class, "<init>", String.class, String.class, String.class,
                 int.class, void.class), null);

core/src/main/java/org/teavm/backend/javascript/rendering/RuntimeRenderer.java

@@ -44,6 +44,10 @@ public class RuntimeRenderer {
             String.class, String.class);
     private static final MethodDescriptor CURRENT_THREAD_METHOD = new MethodDescriptor("currentThread",
             Thread.class);
+    private static final MethodReference STACK_TRACE_ELEM_INIT = new MethodReference(StackTraceElement.class,
+            "<init>", String.class, String.class, String.class, int.class, void.class);
+    private static final MethodReference SET_STACK_TRACE_METHOD = new MethodReference(Throwable.class,
+            "setStackTrace", StackTraceElement[].class, void.class);
 
     private final ClassReaderSource classSource;
     private final NamingStrategy naming;
@@ -197,26 +201,37 @@ public class RuntimeRenderer {
     }
 
     private void renderCreateStackTraceElement() throws IOException {
+        ClassReader cls = classSource.get(STACK_TRACE_ELEM_INIT.getClassName());
+        boolean supported = cls != null && cls.getMethod(STACK_TRACE_ELEM_INIT.getDescriptor()) != null;
+
         writer.append("function $rt_createStackElement(")
                 .append("className,").ws()
                 .append("methodName,").ws()
                 .append("fileName,").ws()
                 .append("lineNumber)").ws().append("{").indent().softNewLine();
         writer.append("return ");
-        writer.append(writer.getNaming().getNameForInit(new MethodReference(StackTraceElement.class,
+        if (supported) {
-                "<init>", String.class, String.class, String.class, int.class, void.class)));
+            writer.append(writer.getNaming().getNameForInit(STACK_TRACE_ELEM_INIT));
             writer.append("(className,").ws()
                     .append("methodName,").ws()
                     .append("fileName,").ws()
-                .append("lineNumber);").softNewLine();
+                    .append("lineNumber)");
+        } else {
+            writer.append("null");
+        }
+        writer.append(";").softNewLine();
         writer.outdent().append("}").newLine();
     }
 
     private void renderSetStackTrace() throws IOException {
+        ClassReader cls = classSource.get(SET_STACK_TRACE_METHOD.getClassName());
+        boolean supported = cls != null && cls.getMethod(SET_STACK_TRACE_METHOD.getDescriptor()) != null;
+
         writer.append("function $rt_setStack(e,").ws().append("stack)").ws().append("{").indent().softNewLine();
-        writer.appendMethodBody(new MethodReference(Throwable.class, "setStackTrace", StackTraceElement[].class,
+        if (supported) {
-                void.class));
+            writer.appendMethodBody(SET_STACK_TRACE_METHOD);
             writer.append("(e,").ws().append("stack);").softNewLine();
+        }
         writer.outdent().append("}").newLine();
     }
 }

core/src/main/resources/org/teavm/backend/javascript/runtime.js

@@ -231,14 +231,23 @@ function $rt_exception(ex) {
         if (typeof $rt_decodeStack === "function" && err.stack) {
             var stack = $rt_decodeStack(err.stack);
             var javaStack = $rt_createArray($rt_objcls(), stack.length);
+            var elem;
+            var noStack = false;
             for (var i = 0; i < stack.length; ++i) {
                 var element = stack[i];
-                javaStack.data[i] = $rt_createStackElement($rt_str(element.className),
+                elem = $rt_createStackElement($rt_str(element.className),
                         $rt_str(element.methodName), $rt_str(element.fileName), element.lineNumber);
+                if (elem == null) {
+                    noStack = true;
+                    break;
                 }
+                javaStack.data[i] = elem;
+            }
+            if (!noStack) {
                 $rt_setStack(ex, javaStack);
             }
         }
+    }
     return err;
 }
 function $rt_createMultiArray(cls, dimensions) {

tools/junit/src/main/java/org/teavm/junit/TeaVMTestRunner.java

@@ -559,6 +559,7 @@ public class TeaVMTestRunner extends Runner implements Filterable {
             JavaScriptTarget target = new JavaScriptTarget();
             if (decodeStack) {
                 target.setDebugEmitter(debugEmitter);
+                target.setStackTraceIncluded(true);
             }
             return target;
         };