* [Bug default/25042] abidw aborts on clang compiled gdbm shared library
2019-01-01 0:00 [Bug default/25042] New: abidw aborts on clang compiled gdbm shared library woodard at redhat dot com
@ 2019-01-01 0:00 ` dodji at redhat dot com
2019-01-01 0:00 ` dodji at redhat dot com
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: dodji at redhat dot com @ 2019-01-01 0:00 UTC (permalink / raw)
To: libabigail
https://sourceware.org/bugzilla/show_bug.cgi?id=25042
dodji at redhat dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #6 from dodji at redhat dot com ---
Closing this thus.
--
You are receiving this mail because:
You are on the CC list for the bug.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug default/25042] abidw aborts on clang compiled gdbm shared library
2019-01-01 0:00 [Bug default/25042] New: abidw aborts on clang compiled gdbm shared library woodard at redhat dot com
2019-01-01 0:00 ` [Bug default/25042] " dodji at redhat dot com
@ 2019-01-01 0:00 ` dodji at redhat dot com
2019-01-01 0:00 ` dodji at redhat dot com
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: dodji at redhat dot com @ 2019-01-01 0:00 UTC (permalink / raw)
To: libabigail
https://sourceware.org/bugzilla/show_bug.cgi?id=25042
--- Comment #4 from dodji at redhat dot com ---
"mark at klomp dot org" <sourceware-bugzilla@sourceware.org> writes:
> I see compare_dies_string_attribute_value () does, so it can do a pointer
> comparison instead of doing a full string comparison.
[...]
Right we really need that optimization because we do type de-duplication
at the DWARF level.
> How much "speedup" do you get from that "optimization"?
String comparisons dominates the profile when doing type de-duplication.
I don't recall the speed-up right now (I've worked on tons of speed
optimizations left and right, all guided by careful profiling), but
suffice it to say that the string comparison was absolutely necessary to
make the speed of the de-duplication (at the DWARF level) be acceptable
at the time. The de-duplication itself being a major size optimization.
This is of course in the context of huge C binaries like the linux
kernel. I haven't implemented this for C++ binaries yet, but at some
point I think it'll be necessary to look into it as we still have bugs
open about libabigail being slow on huge C++ binaries.
> But I think the logic there is broken, especially when dealing with
> split-dwarf DWO files.
Well, libabigail doesn't yet support DWO files, so I wouldn't worry
about that at this point.
When we do support split-dwarf DWO files, then my understanding is that
type de-duplication would then be un-necessary because the
de-duplication would have been done by the DWARF emitter already, by
construction. At that point, this optimization will be unnecessary,
hopefully.
But until then and for all the cases where we need to support non-DWO
files, I think this optimization will be necessary. Anyhow, this
comparison speed-up is encapsulated at one place so when it becomes
unnecessary, it's easy to do away with.
So should we really worry about this?
--
You are receiving this mail because:
You are on the CC list for the bug.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug default/25042] abidw aborts on clang compiled gdbm shared library
2019-01-01 0:00 [Bug default/25042] New: abidw aborts on clang compiled gdbm shared library woodard at redhat dot com
2019-01-01 0:00 ` [Bug default/25042] " dodji at redhat dot com
2019-01-01 0:00 ` dodji at redhat dot com
@ 2019-01-01 0:00 ` dodji at redhat dot com
2019-01-01 0:00 ` dodji at redhat dot com
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: dodji at redhat dot com @ 2019-01-01 0:00 UTC (permalink / raw)
To: libabigail
https://sourceware.org/bugzilla/show_bug.cgi?id=25042
dodji at redhat dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
--- Comment #2 from dodji at redhat dot com ---
Ah, this looks like we need to support the DWARF forms DW_FORM_strx{1,4} from
DWARF5.
I am on it.
Thanks for reporting this!
--
You are receiving this mail because:
You are on the CC list for the bug.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug default/25042] abidw aborts on clang compiled gdbm shared library
2019-01-01 0:00 [Bug default/25042] New: abidw aborts on clang compiled gdbm shared library woodard at redhat dot com
` (2 preceding siblings ...)
2019-01-01 0:00 ` dodji at redhat dot com
@ 2019-01-01 0:00 ` dodji at redhat dot com
2019-01-01 0:00 ` woodard at redhat dot com
2019-01-01 0:00 ` mark at klomp dot org
5 siblings, 0 replies; 7+ messages in thread
From: dodji at redhat dot com @ 2019-01-01 0:00 UTC (permalink / raw)
To: libabigail
https://sourceware.org/bugzilla/show_bug.cgi?id=25042
--- Comment #5 from dodji at redhat dot com ---
This should now be fixed by commits
https://sourceware.org/git/gitweb.cgi?p=libabigail.git;a=commit;h=568dee18a1358e79047e94d10f7eee6f4632464c
and
https://sourceware.org/git/gitweb.cgi?p=libabigail.git;a=commit;h=1f53d1faa90f119d946f6fc7db9c09c2af767cb5.
The fix should be available in the upcoming 1.7 release of Libabigail.
Thank you for filling this issue.
--
You are receiving this mail because:
You are on the CC list for the bug.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug default/25042] abidw aborts on clang compiled gdbm shared library
2019-01-01 0:00 [Bug default/25042] New: abidw aborts on clang compiled gdbm shared library woodard at redhat dot com
` (3 preceding siblings ...)
2019-01-01 0:00 ` dodji at redhat dot com
@ 2019-01-01 0:00 ` woodard at redhat dot com
2019-01-01 0:00 ` mark at klomp dot org
5 siblings, 0 replies; 7+ messages in thread
From: woodard at redhat dot com @ 2019-01-01 0:00 UTC (permalink / raw)
To: libabigail
https://sourceware.org/bugzilla/show_bug.cgi?id=25042
--- Comment #1 from Ben Woodard <woodard at redhat dot com> ---
It is confirmed that the dwarf-4 version doesn't crash abidw.
--
You are receiving this mail because:
You are on the CC list for the bug.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug default/25042] abidw aborts on clang compiled gdbm shared library
2019-01-01 0:00 [Bug default/25042] New: abidw aborts on clang compiled gdbm shared library woodard at redhat dot com
` (4 preceding siblings ...)
2019-01-01 0:00 ` woodard at redhat dot com
@ 2019-01-01 0:00 ` mark at klomp dot org
5 siblings, 0 replies; 7+ messages in thread
From: mark at klomp dot org @ 2019-01-01 0:00 UTC (permalink / raw)
To: libabigail
https://sourceware.org/bugzilla/show_bug.cgi?id=25042
Mark Wielaard <mark at klomp dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |mark at klomp dot org
--- Comment #3 from Mark Wielaard <mark at klomp dot org> ---
Note that elfutils libdw should already handle DW_FORM_strx forms since 0.171.
In general you shouldn't need to handle/check the actual DW_FORM an attribute
is encoded with.
I see compare_dies_string_attribute_value () does, so it can do a pointer
comparison instead of doing a full string comparison. But I think the logic
there is broken, especially when dealing with split-dwarf DWO files.
How much "speedup" do you get from that "optimization"?
--
You are receiving this mail because:
You are on the CC list for the bug.
^ permalink raw reply [flat|nested] 7+ messages in thread