[all-commits] [llvm/llvm-project] 1b194e: [Clang] add btf_tag attribute

[yonghong-song via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 1b194ef1ab3b856afb8458fa9c58408360d292cb
      https://github.com/llvm/llvm-project/commit/1b194ef1ab3b856afb8458fa9c58408360d292cb
  Author: Yonghong Song <yhs at fb.com>
  Date:   2021-08-12 (Thu, 12 Aug 2021)

  Changed paths:
    M clang/include/clang/Basic/Attr.td
    M clang/include/clang/Basic/AttrDocs.td
    M clang/include/clang/Sema/Sema.h
    M clang/lib/Sema/SemaDecl.cpp
    M clang/lib/Sema/SemaDeclAttr.cpp
    M clang/test/Misc/pragma-attribute-supported-attributes-list.test
    A clang/test/Sema/attr-btf_tag.c

  Log Message:
  -----------
  [Clang] add btf_tag attribute

A new attribute btf_tag is added. The syntax looks like
  __attribute__((btf_tag(<string>)))

Users may tag a particular structure/member/function/func_parameter/variable
declaration with an arbitrary string and the intention is
that this string is passed to dwarf so it is available for
post-compilation analysis. The string will be also passed
to .BTF section if the target is BPF. For each permitted
declaration, multiple btf_tag's are allowed.
For detailed use cases, please see
  https://lists.llvm.org/pipermail/llvm-dev/2021-June/151009.html

In case that there exist redeclarations, the btf_tag attributes
will be accumulated along with different declarations, and the
last declaration will contain all attributes.

Differential Revision: https://reviews.llvm.org/D106614