Em Sat, Dec 22, 2018 at 11:16:49PM -0800, Yonghong Song escreveu: > BTF_KIND_FUNC is generated by llvm (latest trunk, 8.0 or later). Tested with latest trunk, applied. I also fixed a bug I introduced where BFAs were appearing, i.e. this: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=e066ed0431b648067e70f8445f09346eed166765 Thanks, - Arnaldo > Without BTF_KIND_FUNC support, we will see the following errors, > > -bash-4.4$ cat t.c > struct t { > int a; > char b1:1; > char b2:3; > int c; > } g; > int main() { return 0; } > -bash-4.4$ clang -O2 -target bpf -g -c t.c -Xclang -target-feature -Xclang +dwarfris > > -bash-4.4$ pahole -F btf t.o > BTF: idx: 3, off: 28, Unknown > struct t { > int a; /* 0 4 */ > > /* Bitfield combined with previous fields */ > > <ERROR(__class__fprintf:1342): 5 not found!> > > /* Bitfield combined with previous fields */ > > <ERROR(__class__fprintf:1342): 5 not found!> > int c; /* 8 4 */ > > /* size: 12, cachelines: 1, members: 4 */ > /* last cacheline: 12 bytes */ > > /* BRAIN FART ALERT! 12 != 8 + 0(holes), diff = 4 */ > > }; > -bash-4.4$ > > The reason is that llvm generates BTF_KIND_FUNC which btf_loader does not > recognize. > > This patch added support for BTF_KIND_FUNC. Since BTF_KIND_FUNC represents > a defined subprogram and not a real type. A null type is used to > represent BTF_KIND_FUNC to avoid skipping type index. > > With this fix, > -bash-4.4$ pahole -F btf t.o > struct t { > int a; /* 0 4 */ > char b1:1; /* 4: 0 1 */ > char b2:3; /* 4: 1 1 */ > int c; /* 8 4 */ > > /* size: 12, cachelines: 1, members: 4 */ > /* last cacheline: 12 bytes */ > > /* BRAIN FART ALERT! 12 != 9 + 0(holes), diff = 3 */ > > }; > > Signed-off-by: Yonghong Song <yhs@xxxxxx> > --- > btf_loader.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/btf_loader.c b/btf_loader.c > index eeb0c8b..ad4cd23 100644 > --- a/btf_loader.c > +++ b/btf_loader.c > @@ -421,6 +421,16 @@ static int btf__load_types(struct btf *btf) > vlen = 0; > } else if (type == BTF_KIND_FUNC_PROTO) { > vlen = create_new_subroutine_type(btf, ptr, vlen, type_ptr, type_index); > + } else if (type == BTF_KIND_FUNC) { > + /* BTF_KIND_FUNC corresponding to a defined subprogram. > + * This is not really a type and it won't be referred by any other types > + * either. Since types cannot be skipped, let us replace it with > + * a nullify_type_entry. > + * > + * No warning here since BTF_KIND_FUNC is a legal entry in BTF. > + */ > + cu__table_nullify_type_entry(btf->priv, type_index); > + vlen = 0; > } else { > fprintf(stderr, > "BTF: idx: %d, off: %zd, Unknown\n", > -- > 2.17.1 -- - Arnaldo
