No luck

The issue of the day: sun.misc.Unsafe.

So, in previous post I’ve mentioned the problem with AtomicInteger and sun/misc/Unsafe. I was trying to fix that for another week (there are some problems with Unsafe.getUnsafe(), it failes in a very strange way), but I still failed and decided to workaround this thing. I’ve commented out AtomicInteger usage from the ThreadLocal, and continued running my ‘hello-world’.

Then there were some other problems that appeared. There was another whole-Inferno crash on

initSystemFD_rFileDescriptor_I_rFileDescriptor(
    p0: ref FileDescriptor_obj, p1: int): ref FileDescriptor_obj
{#>>
        p0.fd = sys->fildes(p1);
        return (p0);
}#<<

This is the part of native method of FileDescriptor. That seemed to have absolutely no problems, but it crashed everything! And after some amount of time I understood that I forgot to allocate some space for fd field, and it actually was pointing to the p0 object itself, so I fixed that quite happily.

Then I found out, that there were two methods missing in my FileDescriptor class, like incrementAndGetUseCount and decrementAndGetUseCount. I was really amused, because when I was implementing FileDescriptor class I found absolutely no mention of these in the official sun/oracle docs. I found no of them even in the OpenJDK docs. But they where definitely used in FileInputStream and some others. Just a funny fact :)

So, I’ve successfully fixed my FileDescriptor, and then I’ve got this again:

[sin/misc/Unsafe]
...
sun/misc/Unsafe-><clinit>()
rtload start
rtload java/lang/Class [84 -> 1056] for sun/misc/Unsafe
load class java/lang/Class
loader() exit
rtload end
Getclassclass called, 'sun/misc/Unsafe' asked for class ''
load class 
Switching class '' state to NEW
[]
JLD:e0:: class not found
[JavaClassLoader] Broken: "JLD:e0:: class not found"
sh: 1055 "JavaClassLoader":JLD:e0:: class not found

This is my old bug with Unsafe. Unfortunately, System.out depends on BufferedOutputStream, and it depends on AtomicReference, which uses Unsafe heavily. And it seems that I can’t move forward until I implement this evil class. That’s all for now.

PS: The midterm is finally here! I’m still happy to work with this project, though it sometimes makes me really bored and sad. Lots of the bugs, that are really hard to track and fix. That’s the main problem, I spend way too much time fixing the bad behaviour. But I really beleive, that soon enough I will finish that project and it will be extremelly useful for the community!

Worked on files: - java/appl/java/classloader.b: Classloader runtime code - java/pkg/java/io/FileDescriptor.java - java/pkg/java/io/FileDescriptor_L.b

Inferno developer GSoC log

No luck