I tried porting the .config we're using to the official branch and
couldn't replicate the problem. It's probably something local.
-bw
On Thu, Apr 1, 2021 at 3:00 PM Yonghong Song <yhs@xxxxxx> wrote:
>
>
>
> On 4/1/21 1:56 PM, Bill Wendling wrote:
> > On Thu, Apr 1, 2021 at 12:35 PM Bill Wendling <morbo@xxxxxxxxxx> wrote:
> >>
> >> On Wed, Mar 31, 2021 at 7:58 PM Yonghong Song <yhs@xxxxxx> wrote:
> >>>
> >>> Function cus__merging_cu() is introduced in Commit 39227909db3c
> >>> ("dwarf_loader: Permit merging all DWARF CU's for clang LTO built
> >>> binary") to test whether cross-cu references may happen.
> >>> The original implementation anticipates compilation flags
> >>> in dwarf, but later some concerns about binary size surfaced
> >>> and the decision is to scan .debug_abbrev as a faster way
> >>> to check cross-cu references. Also putting a note in vmlinux
> >>> to indicate whether lto is enabled for built or not can
> >>> provide a much faster way.
> >>>
> >>> This patch set implemented this two approaches, first
> >>> checking the note (in Patch #2), if not found, then
> >>> check .debug_abbrev (in Patch #1).
> >>>
> >>> Yonghong Song (2):
> >>> dwarf_loader: check .debug_abbrev for cross-cu references
> >>> dwarf_loader: check .notes section for lto build info
> >>>
> >>> dwarf_loader.c | 76 ++++++++++++++++++++++++++++++++++++--------------
> >>> 1 file changed, 55 insertions(+), 21 deletions(-)
> >>>
> >> With this series of patches, the compilation passes for me with
> >> ThinLTO. You may add this if you like:
> >>
> >> Tested-by: Bill Wendling <morbo@xxxxxxxxxx>
> >
> > I did notice these warnings following the "pahole -J .tmp_vmlinux.btf"
> > command. I don't know the severity of them, but it might be good to
> > investigate.
> >
> > $ ./tools/bpf/resolve_btfids/resolve_btfids vmlinux
> > BTFIDS vmlinux
> > WARN: multiple IDs found for 'inode': 355, 8746 - using 355
> > WARN: multiple IDs found for 'file': 588, 8779 - using 588
> > WARN: multiple IDs found for 'path': 411, 8780 - using 411
> > WARN: multiple IDs found for 'seq_file': 1414, 8836 - using 1414
> > WARN: multiple IDs found for 'vm_area_struct': 538, 8873 - using 538
> > WARN: multiple IDs found for 'task_struct': 28, 8880 - using 28
> > WARN: multiple IDs found for 'inode': 355, 9484 - using 355
> > WARN: multiple IDs found for 'file': 588, 9517 - using 588
> > WARN: multiple IDs found for 'path': 411, 9518 - using 411
> > WARN: multiple IDs found for 'seq_file': 1414, 9578 - using 1414
> > WARN: multiple IDs found for 'vm_area_struct': 538, 9615 - using 538
> > WARN: multiple IDs found for 'task_struct': 28, 9622 - using 28
> > WARN: multiple IDs found for 'seq_file': 1414, 12223 - using 1414
> > WARN: multiple IDs found for 'file': 588, 12237 - using 588
> > WARN: multiple IDs found for 'path': 411, 12238 - using 411
> > ...
>
> I didn't see it with my config. Maybe you can share your config file?
>
> >
> > -bw
> >
