Re: [PATCH] sparse, llvm: Fix SIGSEGV for extern symbols

["Jonathan Neuschäfer" <j.neuschaefer@gmx.net>]

On Sun, Aug 05, 2012 at 10:47:34PM +0300, Pekka Enberg wrote:
> Jonathan Neuschäfer writes:
> 
>   compiling a little real-world program with sparse-llvm, it segfaulted.
>   Using a tool called "delta"[1] and some bash scripting, I managed to
>   reduce the code to this test case:
> 
>     extern struct foo *foop;
>     extern void func(struct foo *f);
>     int main(int argc, char **argv) {
>         func(foop);
>     }
> 
> The problem is that pseudo_to_value() does not know abou the extern
> symbol because Sparse never calls output_data() on it which registers
> globals with LLVMAddGlobal().
> 
> As explained by Linus, 'extern' symbols are just names with types. They
> don't have any value associated with them, they just have the type and
> the name. Therefore we need to explicitly call LLVMAddGlobal() for
> symbols we have not encountered in pseudo_to_value().
> 
> Reported by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
> Cc: Christopher Li <sparse@chrisli.org>
> Cc: Jeff Garzik <jgarzik@redhat.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Pekka Enberg <penberg@kernel.org>

This fixes the crash, thanks.

Jonathan
--
To unsubscribe from this list: send the line "unsubscribe linux-sparse" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html