4.14-stable review patch. If anyone has any objections, please let me know.
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From: Jiri Olsa jolsa@kernel.org
commit b7a313d84e853049062011d78cb04b6decd12f5c upstream.
The gcc 8 compiler won't compile the python extension code with the following errors (one example):
python.c:830:15: error: cast between incompatible function types from \ ‘PyObject * (*)(struct pyrf_evsel *, PyObject *, PyObject *)’ \ uct _object * (*)(struct pyrf_evsel *, struct _object *, struct _object *)’} to \ ‘PyObject * (*)(PyObject *, PyObject *)’ {aka ‘struct _object * (*)(struct _objeuct \ _object *)’} [-Werror=cast-function-type] .ml_meth = (PyCFunction)pyrf_evsel__open,
The problem with the PyMethodDef::ml_meth callback is that its type is determined based on the PyMethodDef::ml_flags value, which we set as METH_VARARGS | METH_KEYWORDS.
That indicates that the callback is expecting an extra PyObject* arg, and is actually PyCFunctionWithKeywords type, but the base PyMethodDef::ml_meth type stays PyCFunction.
Previous gccs did not find this, gcc8 now does. Fixing this by silencing this warning for python.c build.
Commiter notes:
Do not do that for CC=clang, as it breaks the build in some clang versions, like the ones in fedora up to fedora27:
fedora:25:error: unknown warning option '-Wno-cast-function-type'; did you mean '-Wno-bad-function-cast'? [-Werror,-Wunknown-warning-option] fedora:26:error: unknown warning option '-Wno-cast-function-type'; did you mean '-Wno-bad-function-cast'? [-Werror,-Wunknown-warning-option] fedora:27:error: unknown warning option '-Wno-cast-function-type'; did you mean '-Wno-bad-function-cast'? [-Werror,-Wunknown-warning-option] #
those have:
clang version 3.9.1 (tags/RELEASE_391/final)
The one in rawhide accepts that:
clang version 6.0.0 (tags/RELEASE_600/final)
Signed-off-by: Jiri Olsa jolsa@kernel.org Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: David Ahern dsahern@gmail.com Cc: Josh Poimboeuf jpoimboe@redhat.com Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: Sergey Senozhatsky sergey.senozhatsky.work@gmail.com Link: http://lkml.kernel.org/r/20180319082902.4518-2-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Cc: Ignat Korchagin ignat@cloudflare.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- tools/perf/util/setup.py | 2 ++ 1 file changed, 2 insertions(+)
--- a/tools/perf/util/setup.py +++ b/tools/perf/util/setup.py @@ -28,6 +28,8 @@ class install_lib(_install_lib): cflags = getenv('CFLAGS', '').split() # switch off several checks (need to be at the end of cflags list) cflags += ['-fno-strict-aliasing', '-Wno-write-strings', '-Wno-unused-parameter' ] +if cc != "clang": + cflags += ['-Wno-cast-function-type' ]
src_perf = getenv('srctree') + '/tools/perf' build_lib = getenv('PYTHON_EXTBUILD_LIB')