• Arnaldo Carvalho de Melo's avatar
    tools build: Filter out options and warnings not supported by clang · 41caff45
    Arnaldo Carvalho de Melo authored
    These make the feature check fail when using clang, so remove them just
    like is done in tools/perf/Makefile.config to build perf itself.
    
    Adding -Wno-compound-token-split-by-macro to tools/perf/Makefile.config
    when building with clang is also necessary to avoid these warnings
    turned into errors (-Werror):
    
        CC      /tmp/build/perf/util/scripting-engines/trace-event-perl.o
      In file included from util/scripting-engines/trace-event-perl.c:35:
      In file included from /usr/lib64/perl5/CORE/perl.h:4085:
      In file included from /usr/lib64/perl5/CORE/hv.h:659:
      In file included from /usr/lib64/perl5/CORE/hv_func.h:34:
      In file included from /usr/lib64/perl5/CORE/sbox32_hash.h:4:
      /usr/lib64/perl5/CORE/zaphod32_hash.h:150:5: error: '(' and '{' tokens introducing statement expression appear in different macro expansion contexts [-Werror,-Wcompound-token-split-by-macro]
          ZAPHOD32_SCRAMBLE32(state[0],0x9fade23b);
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      /usr/lib64/perl5/CORE/zaphod32_hash.h:80:38: note: expanded from macro 'ZAPHOD32_SCRAMBLE32'
      #define ZAPHOD32_SCRAMBLE32(v,prime) STMT_START {  \
                                           ^~~~~~~~~~
      /usr/lib64/perl5/CORE/perl.h:737:29: note: expanded from macro 'STMT_START'
      #   define STMT_START   (void)( /* gcc supports "({ STATEMENTS; })" */
                                    ^
      /usr/lib64/perl5/CORE/zaphod32_hash.h:150:5: note: '{' token is here
          ZAPHOD32_SCRAMBLE32(state[0],0x9fade23b);
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      /usr/lib64/perl5/CORE/zaphod32_hash.h:80:49: note: expanded from macro 'ZAPHOD32_SCRAMBLE32'
      #define ZAPHOD32_SCRAMBLE32(v,prime) STMT_START {  \
                                                      ^
      /usr/lib64/perl5/CORE/zaphod32_hash.h:150:5: error: '}' and ')' tokens terminating statement expression appear in different macro expansion contexts [-Werror,-Wcompound-token-split-by-macro]
          ZAPHOD32_SCRAMBLE32(state[0],0x9fade23b);
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      /usr/lib64/perl5/CORE/zaphod32_hash.h:87:41: note: expanded from macro 'ZAPHOD32_SCRAMBLE32'
          v ^= (v>>23);                       \
                                              ^
      /usr/lib64/perl5/CORE/zaphod32_hash.h:150:5: note: ')' token is here
          ZAPHOD32_SCRAMBLE32(state[0],0x9fade23b);
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      /usr/lib64/perl5/CORE/zaphod32_hash.h:88:3: note: expanded from macro 'ZAPHOD32_SCRAMBLE32'
      } STMT_END
        ^~~~~~~~
      /usr/lib64/perl5/CORE/perl.h:738:21: note: expanded from macro 'STMT_END'
      #   define STMT_END     )
                              ^
    
    Please refer to the discussion on the Link: tag below, where Nathan
    clarifies the situation:
    
    <quote>
    acme> And then get to the problems at the end of this message, which seem
    acme> similar to the problem described here:
    acme>
    acme> From  Nathan Chancellor <>
    acme> Subject	[PATCH] mwifiex: Remove unnecessary braces from HostCmd_SET_SEQ_NO_BSS_INFO
    acme>
    acme> https://lkml.org/lkml/2020/9/1/135
    acme>
    acme> So perhaps in this case its better to disable that
    acme> -Werror,-Wcompound-token-split-by-macro when building with clang?
    
    Yes, I think that is probably the best solution. As far as I can tell,
    at least in this file and context, the warning appears harmless, as the
    "create a GNU C statement expression from two different macros" is very
    much intentional, based on the presence of PERL_USE_GCC_BRACE_GROUPS.
    The warning is fixed in upstream Perl by just avoiding creating GNU C
    statement expressions using STMT_START and STMT_END:
    
      https://github.com/Perl/perl5/issues/18780
      https://github.com/Perl/perl5/pull/18984
    
    If I am reading the source code correctly, an alternative to disabling
    the warning would be specifying -DPERL_GCC_BRACE_GROUPS_FORBIDDEN but it
    seems like that might end up impacting more than just this site,
    according to the issue discussion above.
    </quote>
    Based-on-a-patch-by: default avatarSedat Dilek <sedat.dilek@gmail.com>
    Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # Debian/Selfmade LLVM-14 (x86-64)
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Fangrui Song <maskray@google.com>
    Cc: Florian Fainelli <f.fainelli@gmail.com>
    Cc: Ian Rogers <irogers@google.com>
    Cc: Jiri Olsa <jolsa@kernel.org>
    Cc: John Keeping <john@metanate.com>
    Cc: Leo Yan <leo.yan@linaro.org>
    Cc: Michael Petlan <mpetlan@redhat.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Nathan Chancellor <nathan@kernel.org>
    Cc: Nick Desaulniers <ndesaulniers@google.com>
    Link: http://lore.kernel.org/lkml/YkxWcYzph5pC1EK8@kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    41caff45
Makefile.config 38.2 KB