malloc in core.memory.GC

[Steven Schveighoffer]

On Mon, 09 Apr 2012 13:39:10 -0400, Alex Rønne Petersen  
<xtzgzorex at gmail.com> wrote:

> In MCI, I can't provide finalization support when programs running in  
> the VM use the D GC, because that *requires* me to use the Object layout  
> for runtime objects. That's just not nice, since it adds (IIRC) 3 words  
> of data that's basically useless to *me*. It would be nice if the GC  
> supported finalization callbacks similar to how Boehm does it.

Well, considering that there is no reason whatsoever to expect anything  
stored in the block except the exact object it was created with, I see no  
reason why you couldn't store a TypeInfo reference in the block somewhere  
(not part of the object/struct).

This would mean you could determine the type without having the type  
system, and it would mean you would not carry around the extra baggage for  
calling the finalizer from the GC, when the struct is stored on the stack.

I had great success with this when fixing array appending, I don't see why  
it couldn't be done with finalization.  We do need compiler support to  
make sure the struct dtor function pointer gets stored in the TypeInfo,  
not sure if this has already been done.

-Steve