Messages in this thread | | | Date | Tue, 6 Jun 2017 22:59:50 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [RFC] clang: 'unused-function' warning on static inline functions |
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On Tue, 6 Jun 2017, Matthias Kaehlcke wrote:
> Unfortunately as is the patch doesn't work: > > include/linux/compiler-clang.h:20:9: error: 'inline' macro redefined [-Werror,-Wmacro-redefined] > #define inline inline __attribute__((unused)) > ^ > include/linux/compiler-gcc.h:78:9: note: previous definition is here > #define inline inline notrace > > Another version of David's patch (https://lkml.org/lkml/2017/5/24/878) > first undefines 'inline' before redefining it: > > #ifdef inline > #undef inline > #define inline inline __attribute__((unused)) > #endif > > This works at least in the sense of not causing compiler errors. I > couldn't validate if it actually still indicates the compiler to > inline a function, since in any case 'inline' is only a > recommendation. In the few experiments I did without the patch clang > didn't make a difference between static inline and non-inline > functions. > > The redefinition above could be used to fix the build error, however > it would imply to lose the extra attributes from compiler-gcc.h. >
I've followed up with a patch that handles this behavior in compiler-gcc.h since clang defines __GNUC__ as well, so clang gets both compiler-gcc.h and compiler-clang.h behavior.
I've tested it, but please feel free to add your Tested-by for more confidence in the change.
Linus, who currently maintains include/linux/compiler*.h changes? I see only an entry for a sparse maintainer. I'd happily manage a cross compiler setup if it would be helpful to prevent this type of issue in the future. First question would be if there is a minimum gcc major version intended to be supported?
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