RE: Loading native libraries

[Jeroen Frijters]

David P Grove wrote:
> > Archie Cobbs wrote:
> > > Before I go and implement this, does this sound correct 
> to everyone?
> > 
> > I think we desperately need a VMClassLoader.getCallerClassLoader()
> > method. That way we can simply modify the various load/loadLibrary
> > methods to call that. It's also much more efficient to 
> implement and can
> > be interacts better with method inlining. 
> 
> In Jikes RVM we use an internal widget called 
> VM_StackBrowser.  Think of it as an interator on the thread 
> stack.  It supports the following primary functionality: 
> (1) get the VMClass or java.lang.Classloader for the current 
> stackframe 
> (2) move up one stackframe. 
> 
> This is more flexible than getCallerClassLoader, but also 
> much more efficient in that it doesn't force the big nasty [] 
> for the entire stack to be created up-front when the caller 
> almost never wants more than the top few frames.  The 
> implementation works on the stack directly and doesn't create 
> useless objects/arrays of stuff that clients don't actually need. 
> 
> I'd suggest that something like this be adopted by classpath 
> as the low-level interface for walking stakframes.  It can be 
> both efficient and flexible at the same time. 

That's definitely a worthwhile improvement over the array approach, but
I'd still like to see getCallerClassLoader special cased, because that
allows the JIT to inline methods that use it (if you have a JIT that
knows about getCallerClassLoader).

Regards,
Jeroen