[xmlvm-users] memory bug found

[Panayotis K. <pan...@pa...>]

I think I found a serious memory bug with current implementation of xmlvm.

Here is the minimum java code to reproduce this bug:

package xmlvm;
import org.xmlvm.iphone.UIApplication;
import org.xmlvm.iphone.UIView;

public class Main extends UIApplication {
    public void applicationDidFinishLaunching(UIApplication app) {
        testView view = new testView();
    }
    public static void main(String[] args) {
        UIApplication.main(args, Main.class);
    }
    public class testView extends UIView {
        public testView() {
            System.out.println(getFrame().size);
        }
    }
}


the initialization code of testView produces this code:

- (void) __init_xmlvm_Main_testView___xmlvm_Main :(xmlvm_Main*)n1
{
    XMLVMElem _rtmp;
    XMLVMElem _r0;
    XMLVMElem _r1;
    XMLVMElem _r2;
    XMLVMElem _r3;
    _r2.o = self;
    _r3.o = n1;
    _r0.o = JAVA_NULL;
    _r1.o = JAVA_NULL;
    [_r3.o retain];
    [((xmlvm_Main_testView*) _r2.o)->this_0_xmlvm_Main release];
    ((xmlvm_Main_testView*) _r2.o)->this_0_xmlvm_Main = _r3.o;
    [((org_xmlvm_iphone_UIView*) _r2.o) __init_org_xmlvm_iphone_UIView__];
    _r0.o = [java_lang_System _GET_out];
    _r1.o = [((xmlvm_Main_testView*) _r2.o) getFrame__];
    _rtmp.o =  _r1.o;
    _r1.o = ((org_xmlvm_iphone_CGRect*) _r1.o)->size_org_xmlvm_iphone_CGSize;
    [_rtmp.o release];
    _rtmp.o = JAVA_NULL;
    [((java_io_PrintStream*) _r0.o) println___java_lang_Object:_r1.o];
    return;
}



Now, let me copy & paste the code and add some comments, to describe it:
// perform getFrame()
    _r1.o = [((xmlvm_Main_testView*) _r2.o) getFrame__];

// keep result of getFrame() into temporary variable _rtmp
    _rtmp.o =  _r1.o;

// frame's size is received from the structure
    _r1.o = ((org_xmlvm_iphone_CGRect*) _r1.o)->size_org_xmlvm_iphone_CGSize;

// **release frame ** - here is the bug
    [_rtmp.o release];
    _rtmp.o = JAVA_NULL;

// Use CGSize data, although the structure that was encapsulating it (the frame) is already freed! 
    [((java_io_PrintStream*) _r0.o) println___java_lang_Object:_r1.o];



It seems that objects whose member items are used later on, should also be tracked and released ONLY after the inside items are not used any more!
Or, even better, every time a reference with the -> operator is made, also retain this object and properly release it afterwards.

What others do say?