[PATCH dwarves 0/4] btf: support btf_type_tag attribute

[Yonghong Song <yhs@fb.com>]

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(-)

-- 
2.30.2