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* [Bug debug/106263] New: BTF_KIND_FUNC type does not encode linkage
@ 2022-07-11 20:26 ibhagat at gcc dot gnu.org
2022-08-01 17:46 ` [Bug debug/106263] " cvs-commit at gcc dot gnu.org
0 siblings, 1 reply; 2+ messages in thread
From: ibhagat at gcc dot gnu.org @ 2022-07-11 20:26 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106263
Bug ID: 106263
Summary: BTF_KIND_FUNC type does not encode linkage
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
Assignee: unassigned at gcc dot gnu.org
Reporter: ibhagat at gcc dot gnu.org
Target Milestone: ---
GCC generates BTF_KIND_FUNC with vlen set to 0. libbpf expects the vlen field
to include the linkage information.
The issue was reported here:
https://lore.kernel.org/bpf/8735fbcv3x.fsf@oracle.com/
Although GCC is currently generating the BTF_KIND_FUNC as per the BTF format
documentation (see excerpt below), this needs to be changed to allow the tools
to work well with each other.
[Source: https://www.kernel.org/doc/Documentation/bpf/btf.rst]
...
2.2.12 BTF_KIND_FUNC
~~~~~~~~~~~~~~~~~~~~
``struct btf_type`` encoding requirement:
* ``name_off``: offset to a valid C identifier
* ``info.kind_flag``: 0
* ``info.kind``: BTF_KIND_FUNC
* ``info.vlen``: 0
* ``type``: a BTF_KIND_FUNC_PROTO type
...
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug debug/106263] BTF_KIND_FUNC type does not encode linkage
2022-07-11 20:26 [Bug debug/106263] New: BTF_KIND_FUNC type does not encode linkage ibhagat at gcc dot gnu.org
@ 2022-08-01 17:46 ` cvs-commit at gcc dot gnu.org
0 siblings, 0 replies; 2+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-08-01 17:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106263
--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jose E. Marchesi <jemarch@gcc.gnu.org>:
https://gcc.gnu.org/g:32566720f3a9135fa355f0304f024a79f107a1b8
commit r13-1918-g32566720f3a9135fa355f0304f024a79f107a1b8
Author: Jose E. Marchesi <jose.marchesi@oracle.com>
Date: Fri Jul 8 18:32:02 2022 +0200
btf: emit linkage information in BTF_KIND_FUNC entries
The kernel bpftool expects BTF_KIND_FUNC entries in BTF to include an
annotation reflecting the linkage of functions (static, global). For
whatever reason they abuse the `vlen' field of the BTF_KIND_FUNC entry
instead of adding a variable-part to the record like it is done with
other entry kinds.
This patch makes GCC to include this linkage info in BTF_KIND_FUNC
entries.
Tested in bpf-unknown-none target.
gcc/ChangeLog:
PR debug/106263
* ctfc.h (struct ctf_dtdef): Add field linkage.
* ctfc.cc (ctf_add_function): Set ctti_linkage.
* dwarf2ctf.cc (gen_ctf_function_type): Pass a linkage for
function types and subprograms.
* btfout.cc (btf_asm_func_type): Emit linkage information for the
function.
(btf_dtd_emit_preprocess_cb): Propagate the linkage information
for functions.
gcc/testsuite/ChangeLog:
PR debug/106263
* gcc.dg/debug/btf/btf-function-4.c: New test.
* gcc.dg/debug/btf/btf-function-5.c: Likewise.
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2022-07-11 20:26 [Bug debug/106263] New: BTF_KIND_FUNC type does not encode linkage ibhagat at gcc dot gnu.org
2022-08-01 17:46 ` [Bug debug/106263] " cvs-commit at gcc dot gnu.org
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