On Mon, Apr 24, 2023 at 6:56 PM Yonghong Song <yhs@xxxxxxxx> wrote:
>
>
>
> On 4/24/23 5:01 PM, Stanislav Fomichev wrote:
> > From: Peng Wei <pengweiprc@xxxxxxxxxx>
> >
> > Compiling C++ BPF programs with existing bpf_helper_defs.h is not
> > possible due to stricter C++ type conversions. C++ complains
> > about (void *) type conversions:
> >
> > bpf_helper_defs.h:57:67: error: invalid conversion from ‘void*’ to ‘void* (*)(void*, const void*)’ [-fpermissive]
> > 57 | static void *(*bpf_map_lookup_elem)(void *map, const void *key) = (void *) 1;
> > | ^~~~~~~~~~
> > | |
> > | void*
> >
> > Extend bpf_doc.py to use proper function type instead of void.
>
> Could you specify what exactly the compilation command triggering the
> above error?
The following does it for me:
clang++ --include linux/types.h ./tools/lib/bpf/bpf_helper_defs.h
> >
> > Before:
> > static void *(*bpf_map_lookup_elem)(void *map, const void *key) = (void *) 1;
> >
> > After:
> > static void *(*bpf_map_lookup_elem)(void *map, const void *key) = (void *(*)(void *map, const void *key)) 1;
> >
> > Signed-off-by: Peng Wei <pengweiprc@xxxxxxxxxx>
> > Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
> > ---
> > scripts/bpf_doc.py | 7 ++++++-
> > 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py
> > index eaae2ce78381..fa21137a90e7 100755
> > --- a/scripts/bpf_doc.py
> > +++ b/scripts/bpf_doc.py
> > @@ -827,6 +827,9 @@ COMMANDS
> > print(' *{}{}'.format(' \t' if line else '', line))
> >
> > print(' */')
> > + fptr_type = '%s%s(*)(' % (
> > + self.map_type(proto['ret_type']),
> > + ((' ' + proto['ret_star']) if proto['ret_star'] else ''))
> > print('static %s %s(*%s)(' % (self.map_type(proto['ret_type']),
> > proto['ret_star'], proto['name']), end='')
> > comma = ''
> > @@ -845,8 +848,10 @@ COMMANDS
> > one_arg += '{}'.format(n)
> > comma = ', '
> > print(one_arg, end='')
> > + fptr_type += one_arg
> >
> > - print(') = (void *) %d;' % helper.enum_val)
> > + fptr_type += ')'
> > + print(') = (%s) %d;' % (fptr_type, helper.enum_val))
> > print('')
> >
> > ###############################################################################
