41caff459a
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: Sedat 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.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.