Re: Crash of Archer's gdb on mingw (passing null argument to vasprintf)

[Mark Kettenis <mark dot kettenis at xs4all dot nl>]

> From: Joost van der Sluis <joost@cnoc.nl>
> Date: Mon, 03 Oct 2011 11:39:37 +0200
> 
> Hi all,
> 
> Maybe a strange question because it's not about stock gdb but about the
> fedora16-branch from the Archer project. But I know that there are not
> that much mingw/Windows people on the Archer mailinglist, so I ask here.
> 
> In gdbtypes.c there's this code:
> 
>     warning (_("Range for type %s has invalid bounds %s..%s"),
>             TYPE_NAME (type), plongest (TYPE_LOW_BOUND (range_type)),
>             plongest (TYPE_HIGH_BOUND (range_type)));
> 
> This goes wrong when TYPE_NAME (type) is null. Eventually warning()
> leads to a call of vasprintf(), and on Fedora it prints '(NULL)' when it
> encounters a null-parameter. But on mingw it crashes (sigint).
> 
> How to fix this properly? I could add a check for the assignment of
> TYPE_NAME (type). Or should mingw fix their vasprintf implementation? Or
> can I switch to another version of casprintf? (I use the
> mingw-installation from Fedora to cross-compile to mingw)

The C standard doesn't say that printf("%s", NULL) should be treated
specially, so having things crash just as the would for printf("%s",
p) where p is an invalid pointer is perfectly fine.  So blindly
printing TYPE_NAME (type) clearly is the problem here.