[LLVMdev] Garbage collection

[Andrew Haley]

Nicolas Geoffray wrote:

>> For example, I mentioned the "stop the world" function - however since 
>> LLVM defines no primitives for creating threads or synchronizing between 
>> them, its hard to see how this could be part of LLVM proper. 
> 
> So LLVM should not be aware of "stop the world" stuff. It's really a 
> matter of your collector. What LLVM should be aware is the position of 
> safe points in the code. That's the case with Gordon's GCStrategy class. 
> However, to implement "stop the world", runtimes should be able to add 
> runtime-specific code at these safe points. If you could, then adding a 
> cooperative, stop-the-world GC would be straightforward. Just poll a 
> variable during the safe-point. When a collection is required, the 
> collector updates that variable and waits for all threads to poll it.

Yes, I agree.  That's exactly what we need for Shark, which uses Sun's
Java VM.

Andrew.