From 70c87dd1ab14272813bc318959111557ead99d5f Mon Sep 17 00:00:00 2001
From: tuchida <dc578av_adle@yahoo.co.jp>
Date: Wed, 27 Jan 2021 08:56:07 +0900
Subject: [PATCH] Fixed a broken StackMapTable.

---
 .../mozilla/classfile/ClassFileWriter.java    |  8 ++-
 .../classfile/tests/ClassFileWriterTest.java  | 61 +++++++++++++++++++
 2 files changed, 67 insertions(+), 2 deletions(-)
 create mode 100644 testsrc/org/mozilla/classfile/tests/ClassFileWriterTest.java

diff --git a/src/org/mozilla/classfile/ClassFileWriter.java b/src/org/mozilla/classfile/ClassFileWriter.java
index e54498dc21..929f7a0c86 100644
--- a/src/org/mozilla/classfile/ClassFileWriter.java
+++ b/src/org/mozilla/classfile/ClassFileWriter.java
@@ -2176,8 +2176,12 @@ private int execute(int bci) {
                         if (tag == TypeInfo.UNINITIALIZED_VARIABLE(0) ||
                             tag == TypeInfo.UNINITIALIZED_THIS) {
                             if ("<init>".equals(methodName)) {
-                                int newType =
-                                    TypeInfo.OBJECT(itsThisClassIndex);
+                                int newType;
+                                if (tag == TypeInfo.UNINITIALIZED_VARIABLE(0)) {
+                                    newType = TypeInfo.OBJECT(m.getClassName(), itsConstantPool);
+                                } else {
+                                    newType = TypeInfo.OBJECT(itsThisClassIndex);
+                                }
                                 initializeTypeInfo(instType, newType);
                             } else {
                                 throw new IllegalStateException("bad instance");
diff --git a/testsrc/org/mozilla/classfile/tests/ClassFileWriterTest.java b/testsrc/org/mozilla/classfile/tests/ClassFileWriterTest.java
new file mode 100644
index 0000000000..014e783de8
--- /dev/null
+++ b/testsrc/org/mozilla/classfile/tests/ClassFileWriterTest.java
@@ -0,0 +1,61 @@
+package org.mozilla.javascript.classfile.tests;
+
+import java.lang.reflect.Method;
+import java.math.BigInteger;
+
+import org.junit.Test;
+import org.mozilla.classfile.ByteCode;
+import org.mozilla.classfile.ClassFileWriter;
+import org.mozilla.javascript.DefiningClassLoader;
+import static org.mozilla.classfile.ClassFileWriter.ACC_PUBLIC;
+import static org.mozilla.classfile.ClassFileWriter.ACC_STATIC;
+
+import static org.junit.Assert.*;
+
+public class ClassFileWriterTest {
+    @Test
+    public void testStackMapTable() throws Exception {
+        final String CLASS_NAME = "TestStackMapTable";
+        final String METHOD_NAME = "returnObject";
+
+        ClassFileWriter cfw = new ClassFileWriter(CLASS_NAME,
+                                                  "java/lang/Object",
+                                                  "ClassFileWriterTest.java");;
+
+        // public static Object returnObject()
+        cfw.startMethod(METHOD_NAME, "()Ljava/lang/Object;", (short)(ACC_PUBLIC | ACC_STATIC));
+
+        cfw.add(ByteCode.NEW, "java/math/BigInteger");
+        cfw.add(ByteCode.DUP);
+
+        // new byte[]{ 123 }
+        cfw.addPush(1);
+        cfw.add(ByteCode.NEWARRAY, ByteCode.T_BYTE);
+        cfw.add(ByteCode.DUP);
+        cfw.addPush(0);
+        cfw.add(ByteCode.BIPUSH, 123);
+        cfw.add(ByteCode.BASTORE);
+
+        // new java.math.BigInteger(bytes)
+        cfw.addInvoke(ByteCode.INVOKESPECIAL, "java/math/BigInteger", "<init>", "([B)V");
+
+        // generate StackMapTable
+        cfw.add(ByteCode.DUP);
+        int target = cfw.acquireLabel();
+        cfw.add(ByteCode.IFNULL, target);
+        cfw.markLabel(target);
+
+        cfw.add(ByteCode.ARETURN);
+        cfw.stopMethod((short)0);
+
+        byte[] bytecode = cfw.toByteArray();
+        DefiningClassLoader loader = new DefiningClassLoader();
+        Class cl = loader.defineClass(CLASS_NAME, bytecode);
+
+        Method method = cl.getMethod(METHOD_NAME);
+        Object ret = method.invoke(cl);
+
+        assertTrue(ret instanceof BigInteger);
+        assertEquals(ret, new BigInteger(new byte[]{ 123 }));
+    }
+}