Running generated ARM machine code on Android gives UnsupportedOperationException with Java Bitmap objects

Question

We ( http://www.mosync.com ) have compiled our ARM recompiler with the Android NDK which takes our internal byte code and generates ARM machine code. When executing recompiled code we see an enormous increase in performance, with one small exception, we can't use any Java Bitmap operations. The native system uses a function which takes care of all the calls to the Java side which the recompiled code is calling. On the Java (Dalvik) side we then have bindings to Android features. There are no problems while recompiling the code or when executing the machine code. The exact same source code works on Symbian and Windows Mobile 6.x so the recompiler seems to generate correct ARM machine code. Like I said, the problem we have is that we can't use Java Bitmap objects. We have verified that the parameters which are sent from the Java code is correct, and we have tried following the execution down in Android's own JNI systems. The problem is that we get an UnsupportedOperationException with "size must fit in 32 bits.". The problem seems consistent on Android 1.5 to 2.3. We haven't tried the recompiler on any Android 3 devices.

Is this a bug which other people have encountered, I guess other developers have done similar things.

Answer 1

I managed to find a work-around. When I wrap all the Bitmap.createBitmap calls inside a Activity.runOnUiThread() It works.

Answer 2

I found the message in dalvik_system_VMRuntime.c:

/*
 * public native boolean trackExternalAllocation(long size)
 *
 * Asks the VM if <size> bytes can be allocated in an external heap.
 * This information may be used to limit the amount of memory available
 * to Dalvik threads.  Returns false if the VM would rather that the caller
 * did not allocate that much memory.  If the call returns false, the VM
 * will not update its internal counts.
 */
static void Dalvik_dalvik_system_VMRuntime_trackExternalAllocation(
    const u4* args, JValue* pResult)
{
    s8 longSize = GET_ARG_LONG(args, 1);

    /* Fit in 32 bits. */
    if (longSize < 0) {
        dvmThrowException("Ljava/lang/IllegalArgumentException;",
            "size must be positive");
        RETURN_VOID();
    } else if (longSize > INT_MAX) {
        dvmThrowException("Ljava/lang/UnsupportedOperationException;",
            "size must fit in 32 bits");
        RETURN_VOID();
    }
    RETURN_BOOLEAN(dvmTrackExternalAllocation((size_t)longSize));
}

This method is called, for example, from GraphicsJNI::setJavaPixelRef:

size_t size = size64.get32();
jlong jsize = size;  // the VM wants longs for the size
if (reportSizeToVM) {
    //    SkDebugf("-------------- inform VM we've allocated %d bytes\n", size);
    bool r = env->CallBooleanMethod(gVMRuntime_singleton,
                                gVMRuntime_trackExternalAllocationMethodID,
                                jsize);

I would say it seems that the code you're calling is trying to allocate a too big size. If you show the actual Java call which fails and values of all the arguments that you pass to it, it might be easier to find the reason.