Re: [PATCH 1/1 perf-tools-next] tools features: Don't check for libunwind devel files by default

From: Namhyung Kim
Date: Mon Mar 17 2025 - 13:21:13 EST

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CC-ing more people.

On Mon, Mar 17, 2025 at 09:09:20AM -0700, Ian Rogers wrote:
> On Tue, Dec 3, 2024 at 1:08 PM Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote:
> >
> > Since 13e17c9ff49119aa ("perf build: Make libunwind opt-in rather than
> > opt-out"), so we shouldn't by default be testing for its availability at
> > build time in tools/build/features/test-all.c.
> >
> > That test was designed to test the features we expect to be the most
> > common ones in most builds, so if we test build just that file, then we
> > assume the features there are present and will not test one by one.
> >
> > Removing it from test-all.c gets rid of the first impediment for
> > test-all.c to build successfully:
> >
> > $ cat /tmp/build/perf-tools-next/feature/test-all.make.output
> > In file included from test-all.c:62:
> > test-libunwind.c:2:10: fatal error: libunwind.h: No such file or directory
> > 2 | #include <libunwind.h>
> > | ^~~~~~~~~~~~~
> > compilation terminated.
> > $
> >
> > We then get to:
> >
> > $ cat /tmp/build/perf-tools-next/feature/test-all.make.output
> > /usr/bin/ld: cannot find -lunwind-x86_64: No such file or directory
> > /usr/bin/ld: cannot find -lunwind: No such file or directory
> > collect2: error: ld returned 1 exit status
> > $
> >
> > So make all the logic related to setting CFLAGS, LDFLAGS, etc for
> > libunwind to be conditional on NO_LIBWUNWIND=1, which is now the
> > default, now we get a faster build:
> >
> > $ cat /tmp/build/perf-tools-next/feature/test-all.make.output
> > $ ldd /tmp/build/perf-tools-next/feature/test-all.bin
> > linux-vdso.so.1 (0x00007fef04cde000)
> > libdw.so.1 => /lib64/libdw.so.1 (0x00007fef04a49000)
> > libpython3.12.so.1.0 => /lib64/libpython3.12.so.1.0 (0x00007fef04478000)
> > libm.so.6 => /lib64/libm.so.6 (0x00007fef04394000)
> > libtraceevent.so.1 => /lib64/libtraceevent.so.1 (0x00007fef0436c000)
> > libtracefs.so.1 => /lib64/libtracefs.so.1 (0x00007fef04345000)
> > libcrypto.so.3 => /lib64/libcrypto.so.3 (0x00007fef03e95000)
> > libz.so.1 => /lib64/libz.so.1 (0x00007fef03e72000)
> > libelf.so.1 => /lib64/libelf.so.1 (0x00007fef03e56000)
> > libnuma.so.1 => /lib64/libnuma.so.1 (0x00007fef03e48000)
> > libslang.so.2 => /lib64/libslang.so.2 (0x00007fef03b65000)
> > libperl.so.5.38 => /lib64/libperl.so.5.38 (0x00007fef037c6000)
> > libc.so.6 => /lib64/libc.so.6 (0x00007fef035d5000)
> > liblzma.so.5 => /lib64/liblzma.so.5 (0x00007fef035a0000)
> > libzstd.so.1 => /lib64/libzstd.so.1 (0x00007fef034e1000)
> > libbz2.so.1 => /lib64/libbz2.so.1 (0x00007fef034cd000)
> > /lib64/ld-linux-x86-64.so.2 (0x00007fef04ce0000)
> > libcrypt.so.2 => /lib64/libcrypt.so.2 (0x00007fef03495000)
> > $
> >
> > Fixes: 13e17c9ff49119aa ("perf build: Make libunwind opt-in rather than opt-out")
> > Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> > Cc: Ian Rogers <irogers@xxxxxxxxxx>
> > Cc: James Clark <james.clark@xxxxxxxxxx>
> > Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> > Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> > Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> > Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> > ---
> > tools/build/feature/test-all.c | 5 --
> > tools/perf/Makefile.config | 83 ++++++++++++++++++++--------------
> > 2 files changed, 49 insertions(+), 39 deletions(-)
> >
> > diff --git a/tools/build/feature/test-all.c b/tools/build/feature/test-all.c
> > index 59ef3d7fe6a4e771..80ac297f81967171 100644
> > --- a/tools/build/feature/test-all.c
> > +++ b/tools/build/feature/test-all.c
> > @@ -58,10 +58,6 @@
> > # include "test-libelf-getshdrstrndx.c"
> > #undef main
> >
> > -#define main main_test_libunwind
> > -# include "test-libunwind.c"
> > -#undef main
> > -
> > #define main main_test_libslang
> > # include "test-libslang.c"
> > #undef main
> > @@ -184,7 +180,6 @@ int main(int argc, char *argv[])
> > main_test_libelf_getphdrnum();
> > main_test_libelf_gelf_getnote();
> > main_test_libelf_getshdrstrndx();
> > - main_test_libunwind();
> > main_test_libslang();
> > main_test_libbfd();
> > main_test_libbfd_buildid();
> > diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> > index 2916d59c88cd08b2..0e4f6a860ae25339 100644
> > --- a/tools/perf/Makefile.config
> > +++ b/tools/perf/Makefile.config
> > @@ -43,7 +43,9 @@ endif
> > # Additional ARCH settings for ppc
> > ifeq ($(SRCARCH),powerpc)
> > CFLAGS += -I$(OUTPUT)arch/powerpc/include/generated
> > - LIBUNWIND_LIBS := -lunwind -lunwind-ppc64
> > + ifndef NO_LIBUNWIND
> > + LIBUNWIND_LIBS := -lunwind -lunwind-ppc64
> > + endif
>
> Sorry for missing this patch. Given this, and below, are just
> declaring a variable making it NO_LIBUNWIND conditional feels like
> clutter. I'd suggest just keeping the variable unconditionally and
> making the uses conditional (which of course the patch does).

Agreed, we can leave LIBUNWIND_LIBS setting and make it added only if
NO_LIBUNWIND is not set.

Thanks,
Namhyung

>
> Other than this:
> Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>
>
> Thanks,
> Ian
>
> > endif
> >
> > # Additional ARCH settings for x86
> > @@ -53,25 +55,35 @@ ifeq ($(SRCARCH),x86)
> > ifeq (${IS_64_BIT}, 1)
> > CFLAGS += -DHAVE_ARCH_X86_64_SUPPORT
> > ARCH_INCLUDE = ../../arch/x86/lib/memcpy_64.S ../../arch/x86/lib/memset_64.S
> > - LIBUNWIND_LIBS = -lunwind-x86_64 -lunwind -llzma
> > + ifndef NO_LIBUNWIND
> > + LIBUNWIND_LIBS = -lunwind-x86_64 -lunwind -llzma
> > + endif
> > $(call detected,CONFIG_X86_64)
> > else
> > - LIBUNWIND_LIBS = -lunwind-x86 -llzma -lunwind
> > + ifndef NO_LIBUNWIND
> > + LIBUNWIND_LIBS = -lunwind-x86 -llzma -lunwind
> > + endif
> > endif
> > endif
> >
> > ifeq ($(SRCARCH),arm)
> > - LIBUNWIND_LIBS = -lunwind -lunwind-arm
> > + ifndef NO_LIBUNWIND
> > + LIBUNWIND_LIBS = -lunwind -lunwind-arm
> > + endif
> > endif
> >
> > ifeq ($(SRCARCH),arm64)
> > CFLAGS += -I$(OUTPUT)arch/arm64/include/generated
> > - LIBUNWIND_LIBS = -lunwind -lunwind-aarch64
> > + ifndef NO_LIBUNWIND
> > + LIBUNWIND_LIBS = -lunwind -lunwind-aarch64
> > + endif
> > endif
> >
> > ifeq ($(SRCARCH),loongarch)
> > CFLAGS += -I$(OUTPUT)arch/loongarch/include/generated
> > - LIBUNWIND_LIBS = -lunwind -lunwind-loongarch64
> > + ifndef NO_LIBUNWIND
> > + LIBUNWIND_LIBS = -lunwind -lunwind-loongarch64
> > + endif
> > endif
> >
> > ifeq ($(ARCH),s390)
> > @@ -80,7 +92,9 @@ endif
> >
> > ifeq ($(ARCH),mips)
> > CFLAGS += -I$(OUTPUT)arch/mips/include/generated
> > - LIBUNWIND_LIBS = -lunwind -lunwind-mips
> > + ifndef NO_LIBUNWIND
> > + LIBUNWIND_LIBS = -lunwind -lunwind-mips
> > + endif
> > endif
> >
> > ifeq ($(ARCH),riscv)
> > @@ -121,16 +135,18 @@ ifdef LIBUNWIND_DIR
> > $(foreach libunwind_arch,$(LIBUNWIND_ARCHS),$(call libunwind_arch_set_flags,$(libunwind_arch)))
> > endif
> >
> > -# Set per-feature check compilation flags
> > -FEATURE_CHECK_CFLAGS-libunwind = $(LIBUNWIND_CFLAGS)
> > -FEATURE_CHECK_LDFLAGS-libunwind = $(LIBUNWIND_LDFLAGS) $(LIBUNWIND_LIBS)
> > -FEATURE_CHECK_CFLAGS-libunwind-debug-frame = $(LIBUNWIND_CFLAGS)
> > -FEATURE_CHECK_LDFLAGS-libunwind-debug-frame = $(LIBUNWIND_LDFLAGS) $(LIBUNWIND_LIBS)
> > -
> > -FEATURE_CHECK_LDFLAGS-libunwind-arm += -lunwind -lunwind-arm
> > -FEATURE_CHECK_LDFLAGS-libunwind-aarch64 += -lunwind -lunwind-aarch64
> > -FEATURE_CHECK_LDFLAGS-libunwind-x86 += -lunwind -llzma -lunwind-x86
> > -FEATURE_CHECK_LDFLAGS-libunwind-x86_64 += -lunwind -llzma -lunwind-x86_64
> > +ifndef NO_LIBUNWIND
> > + # Set per-feature check compilation flags
> > + FEATURE_CHECK_CFLAGS-libunwind = $(LIBUNWIND_CFLAGS)
> > + FEATURE_CHECK_LDFLAGS-libunwind = $(LIBUNWIND_LDFLAGS) $(LIBUNWIND_LIBS)
> > + FEATURE_CHECK_CFLAGS-libunwind-debug-frame = $(LIBUNWIND_CFLAGS)
> > + FEATURE_CHECK_LDFLAGS-libunwind-debug-frame = $(LIBUNWIND_LDFLAGS) $(LIBUNWIND_LIBS)
> > +
> > + FEATURE_CHECK_LDFLAGS-libunwind-arm += -lunwind -lunwind-arm
> > + FEATURE_CHECK_LDFLAGS-libunwind-aarch64 += -lunwind -lunwind-aarch64
> > + FEATURE_CHECK_LDFLAGS-libunwind-x86 += -lunwind -llzma -lunwind-x86
> > + FEATURE_CHECK_LDFLAGS-libunwind-x86_64 += -lunwind -llzma -lunwind-x86_64
> > +endif
> >
> > FEATURE_CHECK_LDFLAGS-libcrypto = -lcrypto
> >
> > @@ -734,26 +750,25 @@ ifeq ($(dwarf-post-unwind),1)
> > $(call detected,CONFIG_DWARF_UNWIND)
> > endif
> >
> > -ifndef NO_LOCAL_LIBUNWIND
> > - ifeq ($(SRCARCH),$(filter $(SRCARCH),arm arm64))
> > - $(call feature_check,libunwind-debug-frame)
> > - ifneq ($(feature-libunwind-debug-frame), 1)
> > - $(warning No debug_frame support found in libunwind)
> > +ifndef NO_LIBUNWIND
> > + ifndef NO_LOCAL_LIBUNWIND
> > + ifeq ($(SRCARCH),$(filter $(SRCARCH),arm arm64))
> > + $(call feature_check,libunwind-debug-frame)
> > + ifneq ($(feature-libunwind-debug-frame), 1)
> > + $(warning No debug_frame support found in libunwind)
> > + CFLAGS += -DNO_LIBUNWIND_DEBUG_FRAME
> > + endif
> > + else
> > + # non-ARM has no dwarf_find_debug_frame() function:
> > CFLAGS += -DNO_LIBUNWIND_DEBUG_FRAME
> > endif
> > - else
> > - # non-ARM has no dwarf_find_debug_frame() function:
> > - CFLAGS += -DNO_LIBUNWIND_DEBUG_FRAME
> > + EXTLIBS += $(LIBUNWIND_LIBS)
> > + LDFLAGS += $(LIBUNWIND_LIBS)
> > + endif
> > + ifeq ($(findstring -static,${LDFLAGS}),-static)
> > + # gcc -static links libgcc_eh which contans piece of libunwind
> > + LIBUNWIND_LDFLAGS += -Wl,--allow-multiple-definition
> > endif
> > - EXTLIBS += $(LIBUNWIND_LIBS)
> > - LDFLAGS += $(LIBUNWIND_LIBS)
> > -endif
> > -ifeq ($(findstring -static,${LDFLAGS}),-static)
> > - # gcc -static links libgcc_eh which contans piece of libunwind
> > - LIBUNWIND_LDFLAGS += -Wl,--allow-multiple-definition
> > -endif
> > -
> > -ifndef NO_LIBUNWIND
> > CFLAGS += -DHAVE_LIBUNWIND_SUPPORT
> > CFLAGS += $(LIBUNWIND_CFLAGS)
> > LDFLAGS += $(LIBUNWIND_LDFLAGS)
> > --
> > 2.47.0
> >

Next message: Sudeep Holla: "Re: [PATCH 3/9] efi: Remove redundant creation of the "efivars" platform device"
Previous message: Luca Weiss: "Re: [PATCH 1/7] dt-bindings: mailbox: qcom: add compatible for MSM8226 SoC"
In reply to: Ian Rogers: "Re: [PATCH 1/1 perf-tools-next] tools features: Don't check for libunwind devel files by default"
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