From: Marius Storm-Olsen <marius@storm-olsen.com>
Date: Fri, 21 Aug 2009 19:49:42 GMT
Subject: Re: [msysGit] Re: [PATCH 01/14] Fix non-constant array creation
Message-ID: <4A8EFA56.6050001@gmail.com>
In-Reply-To: <9d6091530908210926p61aa5ea6ya6a7b71f940fdf5a@mail.gmail.com>

Janos Laube said the following on 21.08.2009 18:26:
>> MSVC compiles regex.c, so it must handle it. I'm fine with that.
> 
> msvc supports alloca, but regex.c doesn't make use of it per default 
> (you must define HAVE_ALLOCA_H in order to use it). basically _alloca
>  is fine for that task, but be aware that error handling on windows
> is a bit compilicated. when _alloca fails it throws a structured 
> exception, you must reset the stack and use traditional memory 
> allocation as fallback. see 
> http://msdn.microsoft.com/en-us/library/wb1s57t5.aspx. :-)

I must admit that I didn't look much at the surrounding code to know how 
large preimage->nr can get. But assuming variable-length array is 
handled the same way by the compiler as alloca(), and this code seems to 
be performing fine, I guess it's safe to say that this code won't be 
triggering any SEH, and thus we won't need to handle it?

So, given my assumptions I think we can just replace that one line with 
alloca(), nuke the free(), and everything is ok.

--
.marius