Re: Precise GC (was Re: cannot build libjava/gnu/gcj/xlib/natClip.cc)

[Jeff Sturm <jeff dot sturm at appnet dot com>]

Per Bothner wrote:
> void foo (jobject x)
> {
>   struct {
>      jobject x;
>      jobject y;
>      jstring z;
>   } p;
>   _Jv_RegisterPointers(&p, sizeof(*p));
>   try {
>     p.x = x;
>     p.y = ...;
>     p.z = ...;
>   } finally { _Jv_UnRegisterPointers(&p, sizeof(*p))' }
> }
> 
> _Jv_RegisterPointers add the pointers to the root set (after zeroing
> them); _Jv_UnRegisterPointers removes them from the root set.

It seems to me this is unsafe for precise marking if a collection can be invoked
asynchronously after _Jv_RegisterPointers() and before p is initialized.

Method arguments are not explicitly registered by this scheme either.  (And they
could live in registers, for that matter.)

--
Jeff Sturm
jeff.sturm@commerceone.com