[Gc] Custom marking infrastructure

Laurynas Biveinis laurynas.biveinis at gmail.com
Tue Aug 1 02:31:59 PDT 2006

2006/7/27, Boehm, Hans <hans.boehm at hp.com>:
> Your talking about a collector GCC's internal data structures?


> As I recall, the GCC data structures have an explicit small tag in each
> object?

The objects themselves do not have any tags. There are auxilliary data
structures that serve for this purpose - they have pointers to the
objects, function pointers to the automatically generated marking
functions etc.

> It might be easiest to build a slightly custom version of the
> collector that knows how to map those to the existing gc descriptors,
> presumably by looking them up in a table?  That would make it slightly
> harder to use the standard library, but I don't know how much of an
> issue that is.

I'm afraid I'm don't fully get this idea, probably because I'm not too
accustomed to the collector's internals.

On the other hand, I'm thinking that I can patch marking routine
generator in GCC to emit code which is compatible with what the
collector expects.

> How many different object layouts are there?  Another alternative is to
> map them all to different "kinds".

There are many different object layouts.

Thanks for your comments,


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