• Arnaldo Carvalho de Melo's avatar
    tools build: Remove needless libpython-version feature check that breaks test-all fast path · 3d1d57de
    Arnaldo Carvalho de Melo authored
    Since 66dfdff0 ("perf tools: Add Python 3 support") we don't use
    the tools/build/feature/test-libpython-version.c version in any Makefile
    feature check:
    
      $ find tools/ -type f | xargs grep feature-libpython-version
      $
    
    The only place where this was used was removed in 66dfdff0:
    
      -        ifneq ($(feature-libpython-version), 1)
      -          $(warning Python 3 is not yet supported; please set)
      -          $(warning PYTHON and/or PYTHON_CONFIG appropriately.)
      -          $(warning If you also have Python 2 installed, then)
      -          $(warning try something like:)
      -          $(warning $(and ,))
      -          $(warning $(and ,)  make PYTHON=python2)
      -          $(warning $(and ,))
      -          $(warning Otherwise, disable Python support entirely:)
      -          $(warning $(and ,))
      -          $(warning $(and ,)  make NO_LIBPYTHON=1)
      -          $(warning $(and ,))
      -          $(error   $(and ,))
      -        else
      -          LDFLAGS += $(PYTHON_EMBED_LDFLAGS)
      -          EXTLIBS += $(PYTHON_EMBED_LIBADD)
      -          LANG_BINDINGS += $(obj-perf)python/perf.so
      -          $(call detected,CONFIG_LIBPYTHON)
      -        endif
    
    And nowadays we either build with PYTHON=python3 or just install the
    python3 devel packages and perf will build against it.
    
    But the leftover feature-libpython-version check made the fast path
    feature detection to break in all cases except when python2 devel files
    were installed:
    
      $ rpm -qa | grep python.*devel
      python3-devel-3.9.7-1.fc34.x86_64
      $ rm -rf /tmp/build/perf ; mkdir -p /tmp/build/perf ;
      $ make -C tools/perf O=/tmp/build/perf install-bin
      make: Entering directory '/var/home/acme/git/perf/tools/perf'
        BUILD:   Doing 'make -j32' parallel build
        HOSTCC  /tmp/build/perf/fixdep.o
      <SNIP>
      $ cat /tmp/build/perf/feature/test-all.make.output
      In file included from test-all.c:18:
      test-libpython-version.c:5:10: error: #error
          5 |         #error
            |          ^~~~~
      $ ldd ~/bin/perf | grep python
    	libpython3.9.so.1.0 => /lib64/libpython3.9.so.1.0 (0x00007fda6dbcf000)
      $
    
    As python3 is the norm these days, fix this by just removing the unused
    feature-libpython-version feature check, making the test-all fast path
    to work with the common case.
    
    With this:
    
      $ rm -rf /tmp/build/perf ; mkdir -p /tmp/build/perf ;
      $ make -C tools/perf O=/tmp/build/perf install-bin |& head
      make: Entering directory '/var/home/acme/git/perf/tools/perf'
        BUILD:   Doing 'make -j32' parallel build
        HOSTCC  /tmp/build/perf/fixdep.o
        HOSTLD  /tmp/build/perf/fixdep-in.o
        LINK    /tmp/build/perf/fixdep
    
      Auto-detecting system features:
      ...                         dwarf: [ on  ]
      ...            dwarf_getlocations: [ on  ]
      ...                         glibc: [ on  ]
      $ ldd ~/bin/perf | grep python
    	libpython3.9.so.1.0 => /lib64/libpython3.9.so.1.0 (0x00007f58800b0000)
      $ cat /tmp/build/perf/feature/test-all.make.output
      $
    Reviewed-by: default avatarJames Clark <james.clark@arm.com>
    Fixes: 66dfdff0 ("perf tools: Add Python 3 support")
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Ian Rogers <irogers@google.com>
    Cc: Jaroslav Škarvada <jskarvad@redhat.com>
    Cc: Jiri Olsa <jolsa@kernel.org>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Link: https://lore.kernel.org/lkml/YaYmeeC6CS2b8OSz@kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    3d1d57de
Makefile 9.34 KB