From: Arnaldo Carvalho de Melo acme@redhat.com
commit 41caff459a5b956b3e23ba9ca759dd0629ad3dda upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/build/feature/Makefile | 7 +++++++ tools/perf/Makefile.config | 3 +++ 2 files changed, 10 insertions(+)
--- a/tools/build/feature/Makefile +++ b/tools/build/feature/Makefile @@ -220,6 +220,13 @@ PERL_EMBED_LIBADD = $(call grep-libs,$(P PERL_EMBED_CCOPTS = `perl -MExtUtils::Embed -e ccopts 2>/dev/null` FLAGS_PERL_EMBED=$(PERL_EMBED_CCOPTS) $(PERL_EMBED_LDOPTS)
+ifeq ($(CC_NO_CLANG), 0) + PERL_EMBED_LDOPTS := $(filter-out -specs=%,$(PERL_EMBED_LDOPTS)) + PERL_EMBED_CCOPTS := $(filter-out -flto=auto -ffat-lto-objects, $(PERL_EMBED_CCOPTS)) + PERL_EMBED_CCOPTS := $(filter-out -specs=%,$(PERL_EMBED_CCOPTS)) + FLAGS_PERL_EMBED += -Wno-compound-token-split-by-macro +endif + $(OUTPUT)test-libperl.bin: $(BUILD) $(FLAGS_PERL_EMBED)
--- a/tools/perf/Makefile.config +++ b/tools/perf/Makefile.config @@ -788,6 +788,9 @@ else LDFLAGS += $(PERL_EMBED_LDFLAGS) EXTLIBS += $(PERL_EMBED_LIBADD) CFLAGS += -DHAVE_LIBPERL_SUPPORT + ifeq ($(CC_NO_CLANG), 0) + CFLAGS += -Wno-compound-token-split-by-macro + endif $(call detected,CONFIG_LIBPERL) endif endif