Re: [Qemu-devel] [PATCH] Fix compiler warning (always return a value), introduce qemu_abort?

[Stefan Weil <sw@weilnetz.de>]

Am 26.10.2011 14:54, schrieb Stefan Hajnoczi:
> On Mon, Oct 24, 2011 at 10:18:43PM +0200, Stefan Weil wrote:
>> For compilations with -DNDEBUG, the default case did not return
>> a value which caused a compiler warning.
>>
>> Signed-off-by: Stefan Weil <sw@weilnetz.de>
>> ---
>> hw/ppce500_spin.c | 11 ++++++++---
>> 1 files changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/ppce500_spin.c b/hw/ppce500_spin.c
>> index cccd940..5b5ffe0 100644
>> --- a/hw/ppce500_spin.c
>> +++ b/hw/ppce500_spin.c
>> @@ -168,17 +168,22 @@ static uint64_t spin_read(void *opaque, 
>> target_phys_addr_t addr, unsigned len)
>> {
>> SpinState *s = opaque;
>> uint8_t *spin_p = &((uint8_t*)s->spin)[addr];
>> + uint64_t result = 0;
>>
>> switch (len) {
>> case 1:
>> - return ldub_p(spin_p);
>> + result = ldub_p(spin_p);
>> + break;
>> case 2:
>> - return lduw_p(spin_p);
>> + result = lduw_p(spin_p);
>> + break;
>> case 4:
>> - return ldl_p(spin_p);
>> + result = ldl_p(spin_p);
>> + break;
>> default:
>> assert(0);
>
> I would replace assert(3) with abort(3). If this ever happens the
> program is broken - returning 0 instead of an undefined value doesn't
> help.
>
> Stefan

Alex, do you agree on replacing assert() by abort()?

I personally don't like abort() because it does not show the
reason for the failure.

Most users don't know how to get a core dump or how to
use gdb. And even for those who know, a crash caused
by an abort() which cannot be reproduced usually happens
on a system were ulimit disables core dumps...

I'd like to have a qemu_abort() macro in qemu-common.h which
replaces all abort() calls used today:

#define qemu_abort() \
   do { \
     fprintf(stderr, "QEMU aborted in %s, %s:%u\n", __func__, __FILE__, 
__LINE__);
     abort();
   } while (0)

(The macro could also call a function which handles fprintf and abort).

Cheers,
Stefan W.