Re: GC use within GCC

[Fergus Henderson <fjh at cs dot mu dot oz dot au>]

On 30-Jul-2001, Tom Lord <lord@regexps.com> wrote:
> 
> Am I reading the code of GCC correctly?  It appears that, although GCC
> now uses the Boehm collector, it does not perform a conservative scan
> of the C stack.  Is that true?
> Does GCC use the conservative feature's of boehm-gc at all?  or is
> it being used as an exact collector?

GCC itself doesn't use the Boehm collector.
GCC itself uses its own collector, in gcc/ggc*, which 
	- is type-accurate;
	- requires explicit manual registration of any global variables
	  that might contain pointers to the GC'd heap; and
	- collects only when you explicitly invoke ggc_garbage_collect()
	  (which in most cases means you don't need to explicitly
	  register stuff on the stack).

The Boehm collector is used by the Java runtime.

And for that, yes, the conservative features are being used.
But only Java programs compiled with gcj use it; gcc and cc1 do not.
I don't know off-hand whether the Java front-ent (gcj and java1) uses it,
since I don't know if the Java front-end has any Java source code,
but I don't think so.

-- 
Fergus Henderson <fjh@cs.mu.oz.au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.