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.
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.
Alex