Hi Alex,
On 23 June 2018 at 01:28, Alexander Graf agraf@suse.de wrote:
On 22.06.18 21:28, Simon Glass wrote:
Hi Alex,
On 22 June 2018 at 06:11, Alexander Graf agraf@suse.de wrote:
On 06/21/2018 09:45 PM, Simon Glass wrote:
Hi Alex,
On 21 June 2018 at 03:59, Alexander Graf agraf@suse.de wrote:
On 06/21/2018 04:02 AM, Simon Glass wrote:
Hi Alex,
On 20 June 2018 at 02:56, Alexander Graf agraf@suse.de wrote: > > On 06/20/2018 12:02 AM, Simon Glass wrote: >> >> Hi Alex, >> >> On 18 June 2018 at 08:46, Alexander Graf agraf@suse.de wrote: >>> >>> On 06/18/2018 04:08 PM, Simon Glass wrote: >>>> >>>> There appears to be a bug [1] in gcc when using varargs with this >>>> attribute. Disable it for sandbox so that functions which use that >>>> can >>>> work correctly, such as install_multiple_protocol_interfaces(). >>>> >>>> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70955 >>>> >>>> Signed-off-by: Simon Glass sjg@chromium.org >>> >>> >>> See my patch instead please. >> >> OK I see it now. Do you know what gcc fixes this problem? > > > The bug you found was really just a gcc bug that hit early gcc6 > versions. > I > doubt you're running into it :).
OK, so in fact gcc does not support varargs problems with the ms_abi?
Gcc needs to know whether varargs are sysv varargs or ms varargs. And it differentiates between the two with different variable types for va_list.
Have you seen the builtin_va_list, etc.
I think this sentence is missing content?
I thought that builtin_va_list and friends would work regardless of the calling standard being used. But it looks (from your patch) like you have to explicitly use __builtin_ms_va_list. Is that right?
I'm fairly sure builtin_va_list is just gcc's way of mapping the sysv va_list, but I'm not 100% sure. I can double check with our compiler people next week.
OK looking forward to hearing. I'm not sure when the builtin came in, but if it has been around for a while, and it supports both calling standards, then it would be nice to use it.
Either way, I think this patch is good either way. For starters it's not gcc specific because it uses the normal va_args in the "normal" case. Also, it's not ambiguous. IMHO things are quite clear when reading the code if we explicitly differentiate between sysv and ms_abi va_args.
I'm OK with it since it gets us going.
Reviewed-by: Simon Glass sjg@chromium.org