Re: Extending C with GC?

From	jacobnavia <jacob@jacob.remcomp.fr>
Newsgroups	comp.lang.c
Subject	Re: Extending C with GC?
Date	2016-08-04 21:00 +0200
Organization	A noiseless patient Spider
Message-ID	<no03cf$560$1@dont-email.me> (permalink)
References	<60b33d17-71b7-4ecf-a821-dc641e2673ba@googlegroups.com> <lninvl5sjx.fsf@kst-u.example.com> <lnwpjx1obh.fsf@kst-u.example.com> <kfnvazgil16.fsf@x-alumni2.alumni.caltech.edu>

Show all headers | View raw

Le 04/08/2016 à 17:57, Tim Rentsch a écrit :
> To avoid dealing with ambiguous roots, the language needs to
> operate in an environment where:  one, the type of every memory
> cell is known (so the collector knows whether it's a pointer or
> not);  two, pointers cannot be "disguised" so that they are
> stored in places that the collector doesn't know about.  I think
> it would be very hard for a C implementation to satisfy the first
> property, and essentially impossible to satisfy the second
> property, assuming full C is allowed.

That environment can be provided by the compiler. At each line of code 
there is the Current scope. That scope and all other above it, contain 
data that has types, of course, and all pointers are known. The compiler 
can generate a table of locations within the function, that points to 
the table of all valid pointers in the program and their addresses.

Note that only the pointers marked as GC-pointers will be included in 
the tables. All other pointers are not concerned by the GC. The 
malloc/free system continues to work as always and you can write 
0xdeadbeef into any of those pointers with a simple cast.

GC-pointers however, are not allowed to be cast into anything else but a 
GC-pointer of (maybe) a different type.

GC:
1) From the current frame, mark as used all pointers in the current 
function.

2) Use the stack unwind info to retrieve the calling function, mark 
those until the global scope is reached and mark all that one too.

3) Do this for each thread.

4) Unmarked memory is free.

Note that the info can also be used by a debugger or the user itself if 
the language provides a run time interface. A stack trace of the program
becomes easy to do...

Note that this doesn't imply ANY change to the language besides the 
introduction of the GC-interface names.

Thread

Extending C with GC? luser droog <luser.droog@gmail.com> - 2016-07-31 15:31 -0700
  Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-07-31 15:52 -0700
    Re: Extending C with GC? Tim Rentsch <txr@alumni.caltech.edu> - 2016-07-31 17:21 -0700
    Re: Extending C with GC? Jean-Marc Bourguet <jm@bourguet.org> - 2016-08-01 20:34 +0200
      Re: Extending C with GC? supercat@casperkitty.com - 2016-08-01 12:14 -0700
      Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-01 12:46 -0700
        Re: Extending C with GC? "James R. Kuyper" <jameskuyper@verizon.net> - 2016-08-01 15:56 -0400
          Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-01 14:28 -0700
        Re: Extending C with GC? Jean-Marc Bourguet <jm@bourguet.org> - 2016-08-01 23:37 +0200
          Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-01 15:03 -0700
          Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-02 00:11 +0200
            Re: Extending C with GC? "James R. Kuyper" <jameskuyper@verizon.net> - 2016-08-01 18:19 -0400
              Re: Extending C with GC? BGB <cr88192@hotmail.com> - 2016-08-02 12:46 -0500
    Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-03 15:26 -0700
      Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-03 15:49 -0700
        Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-04 14:07 +1200
          Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-03 19:26 -0700
            Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-04 14:55 +1200
          Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-03 20:38 -0700
            Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-04 05:10 -0700
              Re: Extending C with GC? Siri Cruise <chine.bleu@yahoo.com> - 2016-08-04 05:57 -0700
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-04 06:13 -0700
              Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-05 07:24 +1200
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-04 12:47 -0700
                Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-04 23:32 -0700
                Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-05 10:09 +0100
                Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-05 20:32 +1200
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-05 06:14 -0700
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 04:14 -0700
                Re: Extending C with GC? Melzzzzz <mel@zzzzz.com> - 2016-08-06 13:23 +0200
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 04:38 -0700
                Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-06 04:34 -0700
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 05:28 -0700
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 06:05 -0700
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 06:12 -0700
                Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-06 14:02 +0100
                Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-06 06:11 -0700
                Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-06 14:50 +0100
                Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-06 07:57 -0700
                Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-06 17:02 +0100
                Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-06 19:20 +0200
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-06 14:27 +0100
                Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-06 14:45 +0100
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 09:59 -0700
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-06 19:38 +0100
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 17:03 -0700
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 09:54 +0100
                Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-07 21:53 +1200
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 11:34 +0100
                Re: Extending C with GC? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-08-07 12:06 +0000
                Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-07 14:10 +0100
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 15:38 +0100
                Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-07 14:32 -0700
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 23:44 +0100
                Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-07 16:12 -0700
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 01:42 +0100
                Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-07 18:56 -0700
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 10:20 +0100
                Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-08 09:39 -0700
                Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-08 02:30 +0100
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 20:15 +0100
                Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-08 01:24 +0100
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 02:08 +0100
                Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-07 18:49 -0700
                Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-08 03:28 +0100
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 12:14 +0100
                Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 07:37 +1200
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 20:56 +0100
                Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 08:11 +1200
                Re: Extending C with GC? Melzzzzz <mel@zzzzz.com> - 2016-08-07 22:19 +0200
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 22:23 +0100
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-07 14:29 -0700
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-07 22:36 +0100
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-07 15:04 -0700
                Re: Extending C with GC? jameskuyper@verizon.net - 2016-08-07 15:19 -0700
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 00:04 +0100
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-07 16:20 -0700
                Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 15:21 +1200
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 10:35 +0100
                Re: Extending C with GC? Gareth Owen <gwowen@gmail.com> - 2016-08-08 18:13 +0100
                Re: Extending C with GC? supercat@casperkitty.com - 2016-08-08 11:53 -0700
                Re: Extending C with GC? raltbos@xs4all.nl (Richard Bos) - 2016-08-10 12:58 +0000
                Re: Extending C with GC? supercat@casperkitty.com - 2016-08-10 07:05 -0700
                Re: Extending C with GC? Ken Brody <kenbrody@spamcop.net> - 2016-08-10 12:29 -0400
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 21:15 +0100
                Re: Extending C with GC? supercat@casperkitty.com - 2016-08-08 08:57 -0700
                Re: Extending C with GC? luser droog <luser.droog@gmail.com> - 2016-08-07 15:37 -0700
                Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-07 14:58 -0700
                Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 15:26 +1200
                Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-08 10:26 +0200
                Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 21:13 +1200
                Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-08 10:41 +0100
                Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-08 12:00 +0200
                Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 22:07 +1200
                Re: Extending C with GC? David Brown <david.brown@hesbynett.no> - 2016-08-08 12:57 +0200
                Re: Extending C with GC? Gareth Owen <gwowen@gmail.com> - 2016-08-08 18:12 +0100
                Re: Extending C with GC? Ian Collins <ian-news@hotmail.com> - 2016-08-08 21:25 +1200
                Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-08 02:57 -0700
                Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-07 13:28 -0700
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-07 05:42 -0700
                Re: Extending C with GC? Florian Weimer <fw@deneb.enyo.de> - 2016-08-07 11:49 +0200
                Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-06 19:18 +0200
                Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-06 12:35 -0700
                Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-06 19:27 +0200
                Re: Extending C with GC? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-06 10:55 -0700
                Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-06 12:31 -0700
      Re: Extending C with GC? James Kuyper <jameskuyper@verizon.net> - 2016-08-03 22:36 -0400
        Re: Extending C with GC? David Brown <david.brown@hesbynett.no> - 2016-08-04 10:57 +0200
          Re: Extending C with GC? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-08-04 04:09 -0700
            Re: Extending C with GC? David Brown <david.brown@hesbynett.no> - 2016-08-04 14:01 +0200
        Re: Extending C with GC? supercat@casperkitty.com - 2016-08-04 07:52 -0700
      Re: Extending C with GC? Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-04 08:57 -0700
        Re: Extending C with GC? supercat@casperkitty.com - 2016-08-04 09:19 -0700
          Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-04 12:30 -0700
            Re: Extending C with GC? supercat@casperkitty.com - 2016-08-04 15:21 -0700
              Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-04 16:50 -0700
                Re: Extending C with GC? supercat@casperkitty.com - 2016-08-05 07:31 -0700
          Re: Extending C with GC? Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-05 16:01 -0700
        Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-04 21:00 +0200
          Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-04 20:26 +0100
            Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-05 10:37 +0200
              Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-05 15:52 +0100
              Re: Extending C with GC? antispam@math.uni.wroc.pl - 2016-08-21 00:09 +0000
                Re: Extending C with GC? Gareth Owen <gwowen@gmail.com> - 2016-08-21 08:58 +0100
                Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-21 10:48 +0200
                Re: Extending C with GC? "Pascal J. Bourguignon" <pjb@informatimago.com> - 2016-08-21 19:58 +0200
                Re: Extending C with GC? supercat@casperkitty.com - 2016-08-22 08:46 -0700
                Re: Extending C with GC? Öö Tiib <ootiib@hot.ee> - 2016-08-26 02:24 -0700
                Re: Extending C with GC? supercat@casperkitty.com - 2016-08-26 13:37 -0700
                Re: Extending C with GC? Melzzzzz <mel@zzzzz.com> - 2016-08-27 00:41 +0200
                Re: Extending C with GC? Öö Tiib <ootiib@hot.ee> - 2016-08-28 06:12 -0700
            Re: Extending C with GC? BartC <bc@freeuk.com> - 2016-08-05 10:06 +0100
              Re: Extending C with GC? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-05 15:26 +0100
          Re: Extending C with GC? Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-05 08:11 -0700
            Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-05 17:43 +0200
              Re: Extending C with GC? Tim Rentsch <txr@alumni.caltech.edu> - 2016-08-05 15:28 -0700
        Re: Extending C with GC? BGB <cr88192@hotmail.com> - 2016-08-04 17:11 -0500
  Re: Extending C with GC? Tim Rentsch <txr@alumni.caltech.edu> - 2016-07-31 17:35 -0700
  Re: Extending C with GC? jacobnavia <jacob@jacob.remcomp.fr> - 2016-08-01 07:45 +0200
    Re: Extending C with GC? Keith Thompson <kst-u@mib.org> - 2016-08-01 08:49 -0700
    Re: Extending C with GC? supercat@casperkitty.com - 2016-08-01 09:06 -0700
      Re: Extending C with GC? Aleksandar Kuktin <akuktin@gmail.com> - 2016-08-05 18:11 +0000
        Re: Extending C with GC? luser droog <luser.droog@gmail.com> - 2016-08-05 11:24 -0700
  Re: Extending C with GC? "Chris M. Thomasson" <invalid@invalid.invalid> - 2016-08-08 22:12 -0700

csiph-web