| Message ID | 20200528144023.10814-4-roger.pau@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Clang/LLVM build fixes | expand |
Hi Roger, On 28/05/2020 15:40, Roger Pau Monne wrote: > Clang doesn't support attribute error, and the possible equivalents > like diagnose_if don't seem to work well in this case as they trigger > when when the function is not called (just by being used by the > APPEND_CALL macro). OOI, could you share the diagnose_if change you tried? > > Define nocall to a noop on clang until a proper solution can be found. > > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Acked-by: Julien Grall <jgrall@amazon.com> > --- > xen/include/xen/compiler.h | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/xen/include/xen/compiler.h b/xen/include/xen/compiler.h > index c22439b7a4..225e09e5f7 100644 > --- a/xen/include/xen/compiler.h > +++ b/xen/include/xen/compiler.h > @@ -20,7 +20,11 @@ > > #define __weak __attribute__((__weak__)) > > -#define nocall __attribute__((error("Nonstandard ABI"))) > +#if !defined(__clang__) > +# define nocall __attribute__((error("Nonstandard ABI"))) > +#else > +# define nocall > +#endif > > #if (!defined(__clang__) && (__GNUC__ == 4) && (__GNUC_MINOR__ < 5)) > #define unreachable() do {} while (1) > Cheers,
On Fri, May 29, 2020 at 08:25:44AM +0100, Julien Grall wrote: > Hi Roger, > > On 28/05/2020 15:40, Roger Pau Monne wrote: > > Clang doesn't support attribute error, and the possible equivalents > > like diagnose_if don't seem to work well in this case as they trigger > > when when the function is not called (just by being used by the > > APPEND_CALL macro). > > OOI, could you share the diagnose_if change you tried? I've sent a reduced version to the llvm-dev mailing list, because I think the documentation should be fixed for diagnose_if. The email with the example is at: http://lists.llvm.org/pipermail/llvm-dev/2020-May/141908.html FWIW, using the deprecated attribute will also trigger the same error/warning even when not calling the function from C. > > > > Define nocall to a noop on clang until a proper solution can be found. > > > > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> > > Acked-by: Julien Grall <jgrall@amazon.com> Thanks!
Hi, On 29/05/2020 09:31, Roger Pau Monné wrote: > On Fri, May 29, 2020 at 08:25:44AM +0100, Julien Grall wrote: >> Hi Roger, >> >> On 28/05/2020 15:40, Roger Pau Monne wrote: >>> Clang doesn't support attribute error, and the possible equivalents >>> like diagnose_if don't seem to work well in this case as they trigger >>> when when the function is not called (just by being used by the >>> APPEND_CALL macro). >> >> OOI, could you share the diagnose_if change you tried? > > I've sent a reduced version to the llvm-dev mailing list, because I > think the documentation should be fixed for diagnose_if. The email > with the example is at: > > http://lists.llvm.org/pipermail/llvm-dev/2020-May/141908.html Thanks! > > FWIW, using the deprecated attribute will also trigger the same > error/warning even when not calling the function from C. I read the documentation before asking the code and I did wonder why diagnose_if wouldn't work. I am guessing the behavior wasn't intended. Cheers,
On 28.05.2020 16:40, Roger Pau Monne wrote: > --- a/xen/include/xen/compiler.h > +++ b/xen/include/xen/compiler.h > @@ -20,7 +20,11 @@ > > #define __weak __attribute__((__weak__)) > > -#define nocall __attribute__((error("Nonstandard ABI"))) > +#if !defined(__clang__) > +# define nocall __attribute__((error("Nonstandard ABI"))) I think a blank wants dropping from here. I also should have noticed already on Andrew's putting in of this construct that in a header we'd better use __error__. Both can easily be taken care of while committing. Jan
diff --git a/xen/include/xen/compiler.h b/xen/include/xen/compiler.h index c22439b7a4..225e09e5f7 100644 --- a/xen/include/xen/compiler.h +++ b/xen/include/xen/compiler.h @@ -20,7 +20,11 @@ #define __weak __attribute__((__weak__)) -#define nocall __attribute__((error("Nonstandard ABI"))) +#if !defined(__clang__) +# define nocall __attribute__((error("Nonstandard ABI"))) +#else +# define nocall +#endif #if (!defined(__clang__) && (__GNUC__ == 4) && (__GNUC_MINOR__ < 5)) #define unreachable() do {} while (1)
Clang doesn't support attribute error, and the possible equivalents like diagnose_if don't seem to work well in this case as they trigger when when the function is not called (just by being used by the APPEND_CALL macro). Define nocall to a noop on clang until a proper solution can be found. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> --- xen/include/xen/compiler.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)