Re: [PATCH v2 00/11] perftool-testsuite 2nd batch

[Namhyung Kim <namhyung@kernel.org>]

On Thu, Sep 19, 2024 at 03:14:40PM +0200, Veronika Molnarova wrote:
> 
> 
> On 9/12/24 15:07, Arnaldo Carvalho de Melo wrote:
> > On Thu, Sep 05, 2024 at 04:15:28PM -0300, Arnaldo Carvalho de Melo wrote:
> >> On Thu, Sep 05, 2024 at 04:04:29PM -0300, Arnaldo Carvalho de Melo wrote:
> >>> So, I proposed that if we get that error message (A function DIE doesn't
> >>> have decl_line. Maybe broken DWARF?) we should skip it, but Veronika did
> >>> the right thing and asked if that wasn't really papering over some
> >>> problem and pointed to a patch that addressed a problem that lead to
> >>> that exact same message being produced, but that didn't help with our
> >>> current case, with another blacklisted function, warn_thunk_thunk.
> > 
> >>> You mentioned that this is an asm function, so no DWARF, let alone
> >>> correct DWARF, so the message is kinda ok, but we can't use that message
> >>> as it could paper over real problems like the one fixed by the patch
> >>> that Veronika pointed out.
> > 
> >>> How to figure out if a function has valid DWARF? Maybe for the moment we
> >>> should have _another_ blacklist, one for functions in the blacklist that
> >>> have no valid DWARF? A blacklist's blacklist?
> >  
> >> We have the needed info to provide a more informative warning:
> > 
> > So, perhaps we should, in the test, when we get that "broken dwarf"
> > output, look at the debuginfo file for the kernel to see if the function
> > is one in a DW_UT_compile (CU) that has 
> > 
> >      <da27a>   DW_AT_language    : 32769 (MIPS assembler)
> > 
> > And then just have a -vv output stating that that function is being
> > skipped because it is DWARF from assembler?
> > 
> > Veronika, would you be willing to try to do that?
> 
> Okay, I can try to parse the debuginfo to check the DWARF.
 
I'll wait for v3 then.

Thanks,
Namhyung