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From: "david.faust at oracle dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/106773] libbpf: failed to find BTF info for
 global/extern symbol 'bpf_link_fops'
Date: Tue, 29 Nov 2022 00:44:00 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106773

--- Comment #3 from David Faust <david.faust at oracle dot com> ---
There are two remaining issues:

1. We are missing support for 'linkage=3Dextern' encoding for variables,
   so 'bpf_link_fops' and others are incorrectly marked with 'linkage=3Dglo=
bal'
   instead.

2. 'bpf_link_fops' variable is encoded as 'void' type not 'const void'.
   This is a result of the BTF being generated from internal DWARF
   representation. The distinction seems to be intentionally removed in
   dwarf2out.cc:add_type_attribute(), with the later side-effect that
   looking up the type DIE for the variable when generating BTF actually
   fails and falls back to the default 'void'.

I have an implementation for (1) in progress. For (2) I need to understand
why the 'void'/'const void' distinction is removed in DWARF and how to work=
=20
around it.=