On 11/15/05, Niko Matsakis <[EMAIL PROTECTED]> wrote: > > As Neal pointed out, it's tricky to write code for the AST parser > > and compiler > > without accidentally letting memory leak when the parser or > > compiler runs into > > a problem and has to bail out on whatever it was doing. Thomas's > > patch got to > > v5 (based on Neal's review comments) with memory leaks still in it, > > my review > > got rid of some of them, and we think Neal's last review of v6 of > > the patch > > got rid of the last of them. > > Another lurker's 2 cents: > > My experience with compilers in particular is that an arena is the > way to go for memory management. I haven't looked at the AST code, > but this can take a variety of forms: anything from linked lists of > pointers to free from something which allocates memory in large > blocks and parcels them out. The goal is just to be able to free the > memory en-masse whatever happens and not have to track individual > pointers.
Thanks for the message. I was going to suggest the same thing. I think it's primarily a question of how to add an arena layer. The AST phase has a mixture of malloc/free and Python object allocation. It should be straightforward to change the malloc/free code to use an arena API. We'd probably need a separate mechanism to associate a set of PyObject* with the arena and have those DECREFed. Jeremy > > Generally, compilers have memory allocations which operate in phases > and so are very amenable to arenas. You might have one memory pool > for long lived representation, one that is freed and recreated > between passes, etc. > > If you need to keep the AST around long term, then a mark-sweep > garbage collector combined with a linked list might even be a good idea. > > Obviously, the whole thing is a tradeoff of peak memory size (which > goes up) against correctness (which is basically ensured, and at > least easily auditable). > > > Niko > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > http://mail.python.org/mailman/options/python-dev/jeremy%40alum.mit.edu > _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com