From mboxrd@z Thu Jan 1 00:00:00 1970 From: Don Howard To: Andrew Cagney Cc: Fernando Nasser , Michael Snyder , Fernando Nasser , Subject: Re: [RFA] deleting breakpoints inside of 'commands' [Repost] Date: Wed, 19 Sep 2001 09:33:00 -0000 Message-id: References: <3BA8B70D.7040506@cygnus.com> X-SW-Source: 2001-09/msg00254.html On Wed, 19 Sep 2001, Andrew Cagney wrote: > > > > I have the same concerns. > > We haven't heard from Don yet. Maybe he has some compromise solution. > > > > Anyway, I find the copy solution a hack. > > > > One way to fix this is to have the chain of commands as an object with > > use count. It is only freed when the count is down to zero again. > > > > When you associate it with a breakpoint it goes up to 1. When you > > get it to execute it goes up to 2. > > > > When a breakpoint is deleted, it deallocates it. If the count goes > > to zero memory is freed. But if the script is being executed (and > > is deleting self) the count will go to 1 and nothing else happens > > until the script finishes executing and the chain is freed (then > > the count goes to zero and memory is deallocated). > > Rememeber, the patch doesn't have to be perfect, just acceptable. In > this case, the change eliminates a stray pointer problem (which would > likely still occure with reference counters) and hence makes gdb far > more robust - I put robustness and maintainability at a much higher > priority level then performance. > When someone manages to demonstrate that the copy is a significant > overhead (using ``set maint profile on/off'' [:-)]) then I think we > should refine the code to do what you propose (or gasp add a garbage > collector :-/). However, Don, if you're upto the task. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ I don't understand what you are asking here. I've followed the thread and it seems that the unconditional copy is not acceptable. I will look at the suggestions that Fernando and Michael have suggested and see if I can come up with another patch. -- -Don dhoward@redhat.com gdb engineering