Re: [PATCH 5/4] libbacktrace: improve getting debug information for loaded dlls

[Ian Lance Taylor <iant@golang.org>]

On Thu, Jan 25, 2024 at 11:53 AM Björn Schäpers <gcc@hazardy.de> wrote:
>
> Am 23.01.2024 um 23:37 schrieb Ian Lance Taylor:
> > On Thu, Jan 4, 2024 at 2:33 PM Björn Schäpers <gcc@hazardy.de> wrote:
> >>
> >> Am 03.01.2024 um 00:12 schrieb Björn Schäpers:
> >>> Am 30.11.2023 um 20:53 schrieb Ian Lance Taylor:
> >>>> On Fri, Jan 20, 2023 at 2:55 AM Björn Schäpers <gcc@hazardy.de> wrote:
> >>>>>
> >>>>> From: Björn Schäpers <bjoern@hazardy.de>
> >>>>>
> >>>>> Fixes https://github.com/ianlancetaylor/libbacktrace/issues/53, except
> >>>>> that libraries loaded after the backtrace_initialize are not handled.
> >>>>> But as far as I can see that's the same for elf.
> >>>>
> >>>> Thanks, but I don't want a patch that loops using goto statements.
> >>>> Please rewrite to avoid that.  It may be simpler to call a function.
> >>>>
> >>>> Also starting with a module count of 1000 seems like a lot.  Do
> >>>> typical Windows programs load that many modules?
> >>>>
> >>>> Ian
> >>>>
> >>>>
> >>>
> >>> Rewritten using a function.
> >>>
> >>> If that is commited, could you attribute that commit to me (--author="Björn
> >>> Schäpers <bjoern@hazardy.de>")?
> >>>
> >>> Thanks and kind regards,
> >>> Björn.
> >>
> >> I noticed that under 64 bit libraries loaded with LoadLibrary were missing.
> >> EnumProcessModules stated the correct number of modules, but did not fill the
> >> the HMODULEs, but set them to 0. While trying to investigate I noticed if I do
> >> the very same thing from main (in C++) I even got fewer module HMODULEs.
> >>
> >> So I went a different way. This detects all libraries correctly, in 32 and 64
> >> bit. The question is, if it should be a patch on top of the previous, or should
> >> they be merged, or even only this solution and drop the EnumProcessModules variant?
> >
> > Is there any reason to use both patches?  Seems simpler to just use
> > this one if it works.  Thanks.
> >
> > Ian
>
> This one needs the tlhelp32 header and its functions, which are (accoridng to
> the microsoft documentation) are only available since Windows XP rsp. Windows
> Server 2003.
>
> If that's no problem, and in my opinion it shouldn't be, then I can basically
> drop patch 4 and rebase this one.

I don't see that as a problem.  It seems like the patch will fall back
cleanly on ancient Windows and simply fail to pick up other loaded
DLLs.  I think that is fine.  I'll look for an updated patch.  Thanks.

Ian