On Fri, Nov 13, 2020 at 12:14 AM Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx> wrote: > > On Fri, Nov 13, 2020 at 1:09 AM Nick Desaulniers > <ndesaulniers@xxxxxxxxxx> wrote: > > > > Thank you for the explicit diagnostics observed. Something fishy is > > going on though, https://godbolt.org/z/Gbxbxa is how I expect MSVC to > > handle include/linux/compiler_attributes.h. > > > > The C preprocessor should make it such that MSVC never sees > > `__attribute__` or `__fallthrough__`; that it does begs the question. > > That would seem to imply that `#if __has_attribute(__fallthrough__)` > > somehow evaluates to true on MSVC, but my godbolt link shows it does > > not. > > > > Could the upstream ACPICA project be #define'ing something that could > > be altering this? (Or not #define'ing something?) > > > > Worst case, we could do as Joe Perches suggested and disable > > -Wfallthrough for drivers/acpi/acpica/. > > I agree, something is fishy. MSVC has several flags for conformance > and extensions support, including two full C preprocessors in newer > versions; which means we might be missing something, but I don't see > how the code in compiler_attributes.h could be confusing MSVC even in > older non-conforming versions. unless ``` # define fallthrough __attribute__((__fallthrough__)) ``` was copy and pasted into the code, rather than #including the whole header? -- Thanks, ~Nick Desaulniers
