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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	[thread overview]
Message-ID: <bug-106773-4-yagosMcipf@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-106773-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106773

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

1. We are missing support for 'linkage=extern' encoding for variables,
   so 'bpf_link_fops' and others are incorrectly marked with 'linkage=global'
   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 
around it.

  parent reply	other threads:[~2022-11-29  0:44 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-29 22:07 [Bug c/106773] New: " james.hilliard1 at gmail dot com
2022-09-01 20:31 ` [Bug target/106773] " james.hilliard1 at gmail dot com
2022-09-01 22:33 ` james.hilliard1 at gmail dot com
2022-11-29  0:44 ` david.faust at oracle dot com [this message]
2022-11-30 21:20 ` david.faust at oracle dot com
2022-12-01  0:04 ` james.hilliard1 at gmail dot com
2022-12-01  0:12 ` james.hilliard1 at gmail dot com
2022-12-01  2:07 ` james.hilliard1 at gmail dot com
2022-12-01 17:09 ` david.faust at oracle dot com
2022-12-01 21:49 ` david.faust at oracle dot com
2022-12-01 22:09 ` james.hilliard1 at gmail dot com
2022-12-01 22:11 ` james.hilliard1 at gmail dot com
2022-12-01 22:30 ` james.hilliard1 at gmail dot com
2022-12-05 17:42 ` david.faust at oracle dot com
2022-12-05 19:01 ` james.hilliard1 at gmail dot com
2022-12-05 21:06 ` david.faust at oracle dot com
2022-12-05 21:57 ` james.hilliard1 at gmail dot com
2022-12-14 18:25 ` cvs-commit at gcc dot gnu.org
2022-12-14 18:25 ` cvs-commit at gcc dot gnu.org
2022-12-14 18:26 ` cvs-commit at gcc dot gnu.org
2023-01-06 14:18 ` jemarch at gcc dot gnu.org

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