Re: [PATCH 1/1] perf script python: Cope with declarations after statements found in Python.h

[Ian Rogers]

On Wed, Aug 2, 2023 at 6:42 AM Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote:
>
> With -Werror the build was failing on fedora rawhide:
>
>   [perfbuilder@27cfe44d67ed perf-6.5.0-rc2]$ gcc -v
>   Using built-in specs.
>   COLLECT_GCC=gcc
>   COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/13/lto-wrapper
>   OFFLOAD_TARGET_NAMES=nvptx-none
>   OFFLOAD_TARGET_DEFAULT=1
>   Target: x86_64-redhat-linux
>   Configured with: ../configure --enable-bootstrap --enable-languages=c,c++,fortran,objc,obj-c++,ada,go,d,m2,lto --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-shared --enable-threads=posix --enable-checking=release --enable-multilib --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-gcc-major-version-only --enable-libstdcxx-backtrace --with-libstdcxx-zoneinfo=/usr/share/zoneinfo --with-linker-hash-style=gnu --enable-plugin --enable-initfini-array --with-isl=/builddir/build/BUILD/gcc-13.2.1-20230728/obj-x86_64-redhat-linux/isl-install --enable-offload-targets=nvptx-none --without-cuda-driver --enable-offload-defaulted --enable-gnu-indirect-function --enable-cet --with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux --with-build-config=bootstrap-lto --enable-link-serialization=1
>   Thread model: posix
>   Supported LTO compression algorithms: zlib zstd
>   gcc version 13.2.1 20230728 (Red Hat 13.2.1-1) (GCC)
>   [perfbuilder@27cfe44d67ed perf-6.5.0-rc2]$
>
>   In file included from /usr/include/python3.12/Python.h:44,
>                    from scripts/python/Perf-Trace-Util/Context.c:14:
>   /usr/include/python3.12/object.h: In function 'Py_SIZE':
>   /usr/include/python3.12/object.h:217:5: error: ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
>     217 |     PyVarObject *var_ob = _PyVarObject_CAST(ob);
>         |     ^~~~~~~~~~~
>   In file included from /usr/include/python3.12/Python.h:53:
>   /usr/include/python3.12/cpython/longintrepr.h: In function '_PyLong_CompactValue':
>   /usr/include/python3.12/cpython/longintrepr.h:121:5: error: ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
>     121 |     Py_ssize_t sign = 1 - (op->long_value.lv_tag & _PyLong_SIGN_MASK);
>         |     ^~~~~~~~~~
>   <SNIP>
>   In file included from /usr/include/python3.12/Python.h:44,
>                    from util/scripting-engines/trace-event-python.c:22:
>   /usr/include/python3.12/object.h: In function 'Py_SIZE':
>   /usr/include/python3.12/object.h:217:5: error: ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
>     217 |     PyVarObject *var_ob = _PyVarObject_CAST(ob);
>         |     ^~~~~~~~~~~
>     CC      /tmp/build/perf/util/units.o
>     CC      /tmp/build/perf/util/time-utils.o
>   In file included from /usr/include/python3.12/Python.h:53:
>   /usr/include/python3.12/cpython/longintrepr.h: In function '_PyLong_CompactValue':
>   /usr/include/python3.12/cpython/longintrepr.h:121:5: error: ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
>     121 |     Py_ssize_t sign = 1 - (op->long_value.lv_tag & _PyLong_SIGN_MASK);
>         |     ^~~~~~~~~~
>
> So add -Wno-declaration-after-statement to the python scripting CFLAGS.
>
> Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Cc: Ian Rogers <irogers@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Link: https://lore.kernel.org/lkml/
> Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>

Thanks,
Ian

> ---
>  tools/perf/scripts/python/Perf-Trace-Util/Build | 3 ++-
>  tools/perf/util/scripting-engines/Build         | 3 ++-
>  2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/scripts/python/Perf-Trace-Util/Build b/tools/perf/scripts/python/Perf-Trace-Util/Build
> index 7d0e33ce6aba44f4..5b0b5ff7e14afc50 100644
> --- a/tools/perf/scripts/python/Perf-Trace-Util/Build
> +++ b/tools/perf/scripts/python/Perf-Trace-Util/Build
> @@ -1,3 +1,4 @@
>  perf-y += Context.o
>
> -CFLAGS_Context.o += $(PYTHON_EMBED_CCOPTS) -Wno-redundant-decls -Wno-strict-prototypes -Wno-unused-parameter -Wno-nested-externs
> +# -Wno-declaration-after-statement: The python headers have mixed code with declarations (decls after asserts, for instance)
> +CFLAGS_Context.o += $(PYTHON_EMBED_CCOPTS) -Wno-redundant-decls -Wno-strict-prototypes -Wno-unused-parameter -Wno-nested-externs -Wno-declaration-after-statement
> diff --git a/tools/perf/util/scripting-engines/Build b/tools/perf/util/scripting-engines/Build
> index c220fec970324d85..586b94e90f4eb3b8 100644
> --- a/tools/perf/util/scripting-engines/Build
> +++ b/tools/perf/util/scripting-engines/Build
> @@ -5,4 +5,5 @@ perf-$(CONFIG_LIBPYTHON) += trace-event-python.o
>
>  CFLAGS_trace-event-perl.o += $(PERL_EMBED_CCOPTS) -Wno-redundant-decls -Wno-strict-prototypes -Wno-unused-parameter -Wno-shadow -Wno-nested-externs -Wno-undef -Wno-switch-default -Wno-bad-function-cast -Wno-declaration-after-statement -Wno-switch-enum
>
> -CFLAGS_trace-event-python.o += $(PYTHON_EMBED_CCOPTS) -Wno-redundant-decls -Wno-strict-prototypes -Wno-unused-parameter -Wno-shadow -Wno-deprecated-declarations -Wno-switch-enum
> +# -Wno-declaration-after-statement: The python headers have mixed code with declarations (decls after asserts, for instance)
> +CFLAGS_trace-event-python.o += $(PYTHON_EMBED_CCOPTS) -Wno-redundant-decls -Wno-strict-prototypes -Wno-unused-parameter -Wno-shadow -Wno-deprecated-declarations -Wno-switch-enum -Wno-declaration-after-statement
> --
> 2.37.1
>