btf_type_tag is a new llvm type attribute which is used similar
to kernel __user/__rcu attributes. The format of btf_type_tag looks like
__attribute__((btf_type_tag("tag1")))
For the case where the attribute applied to a pointee like
#define __tag1 __attribute__((btf_type_tag("tag1")))
#define __tag2 __attribute__((btf_type_tag("tag2")))
int __tag1 * __tag1 __tag2 *g;
the information will be encoded in dwarf.
In BTF, the attribute is encoded as a new kind
BTF_KIND_TYPE_TAG and latest bpf-next supports it.
The patch added support in pahole, specifically
converts llvm dwarf btf_type_tag attributes to
BTF types. Please see individual patches for details.
Yonghong Song (4):
libbpf: sync with latest libbpf repo
dutil: move DW_TAG_LLVM_annotation definition to dutil.h
dwarf_loader: support btf_type_tag attribute
btf_encoder: support btf_type_tag attribute
btf_encoder.c | 7 +++
dutil.h | 4 ++
dwarf_loader.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++---
dwarves.h | 38 +++++++++++++++-
lib/bpf | 2 +-
pahole.c | 8 ++++
6 files changed, 170 insertions(+), 9 deletions(-)
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2.30.2
