Re: alloca is bad?

[Christopher Faylor <cgf at redhat dot com>]

On Fri, Nov 10, 2000 at 11:42:48AM -0500, Fernando Nasser wrote:
>Chris Faylor wrote:
>> 
>> On Fri, Nov 10, 2000 at 05:39:29AM -0500, Eli Zaretskii wrote:
>> >> Date: Thu, 9 Nov 2000 21:20:32 -0500
>> >> From: Christopher Faylor <cgf@redhat.com>
>> >>
>> >> I was surprised by this assertion and so I thought I'd ask for a
>> >> consensus here.  Should the use of alloca be deprecated in gdb?
>> >
>> >In my experience, there's nothing wrong with alloca as long as it is
>> >used for allocating small buffers.  The only consideration is that not
>> >every platform supports alloca.
>> 
>> But, since alloca is already entrenched in gdb and available in liberty
>> I don't think this is an issue, is it?
>> 
>
>Warning: if the "liberty" alloca() is used a "alloca(0)" must be added to
>our interpreter's command loops or the garbage collection becomes somewhat
>random (it will only happen when you call alloca() for allocating some
>other stuff and will only clean what was allocated by code that executed on frames
>below the current stack position.
>
>I think we have this bug when alloca() gets used right now.
>
>(Nothing difficult, we just need to remember to do it)

% fgrep 'alloca (0)' *.c
gnu-regex.c:      alloca (0);
gnu-regex.c:  alloca (0);
gnu-regex.c:  alloca (0);
regcache.c:  alloca (0);
top.c:  alloca (0);

cgf