== Linaro GCC ==
* Finish testing for big-endian/quad-word patch on mainline, and
send upstream. Not yet reviewed by an ARM maintainer, but Joseph
suggested tweaking DejaGnu's target-supports to better reflect the new
capabilities of the vectorizer in big-endian mode. I've not looked into
that yet.
* Started looking at improving element/structure load/store intrinsics.
Made it so that the structs used for loads/stores are created in the
backend so that the types can be used directly by the builtins, but
discovered that the front-end/middle-end would not play along with that
plan as they are. Thought about ways to fix that.
* Some time spent on other CodeSourcery stuff.
The Linaro Toolchain Working Group is pleased to announce the release
of both Linaro GCC 4.4 and Linaro GCC 4.5.
Linaro GCC 4.5 is the fifth release in the 4.5 series. Based off the
latest GCC 4.5.1+svn167157, it includes many ARM-focused performance
improvements and bug fixes.
Linaro GCC 4.4 is the fifth release in the 4.4 series. Based off the
latest GCC 4.4.5, it is a maintenance release that fixes one problem
found through use.
Interesting changes include:
* A new performance focused extension elimination pass
* Speed and size improvements when loading constants
* Performance improvements on compound conditionals
* A range of correctness improvements
The source tarballs are available from:
https://launchpad.net/gcc-linaro/+milestone/4.5-2010.12-0
and
https://launchpad.net/gcc-linaro/+milestone/4.4-2010.12-0
Downloads are available from the Linaro GCC page on Launchpad:
https://launchpad.net/gcc-linaro
No changes have been committed to Linaro GDB 7.2 this month.
-- Michael
* Linaro GCC 4.4/4.5
Merged the latest CS patches and Linaro merge requests into Linaro GCC
(4.4 and 4.5). Ran regression tests. Yao's patch failed so I backed it
out, and made the release tarballs. Uploaded the releases to Michael
Hope for release.
lp:686381: luatex fails to build with gcc-4.5
Fired off a test build to reproduce the problem. Will come back to this
next week.
* GCC 4.6/4.7
Posted my various queued patches up to gcc-patches(a)gcc.gnu.org for review.
Looked at the state of the GCC 4.6 upstream build. There are currently
two problems:
1. libquadmath must be disabled in a cross-build for the bootstrap phases.
2. libstdc++ doesn't build. There is a patch for it on the mail list,
but it's not applied yet.
Once gcc 4.6 builds cleanly, I shall update the Launchpad 4.6 branch,
and declare that the baseline for our development. We'll then have
somewhere to commit and track patches awaiting GCC stage 1 development.
* Other
Caught up with email following my holiday.
Yet again, my IGEPv2 board suffered a corrupt file system. I've now
upgraded the kernel and configured it to use an NFS root. The board is
now somewhat less mobile, but should work more reliably.
Continued organizing the a brain-storming session for GCC optimization
improvements.
Organised flights and hotel for both the Linaro Sprint and CodeSourcery
annual meeting in January.
== Last Week ==
* Spent time tracking down a couple of regressions that appeared in the
new ltrace release-candidate tree. Submitted a bunch of patches to fix
the issues that were discovered during that process; most have been applied.
* Finished writing fairly generic code for handling ARM-specific unwind
tables, from lookup through decoding and dispatch. It uses a few
definitions specific to libunwind, but those probably could be
eliminated with more work.
== This Week ==
* Integrate new ARM-specific bits into libunwind framework.
* Rewrite part of a portability patch for ltrace and hope that those
changes reflect the very last effort that will be required for that
particular task.
--
Zach Welch
CodeSourcery
zwelch(a)codesourcery.com
(650) 331-3385 x743
On Fri, Dec 3, 2010 at 9:06 AM, Yao Qi <yao.qi(a)linaro.org> wrote:
> Hi, Kernel WG,
> Can recent kernel handle NEON registers in corefiles?
>
> Seems we've had plan for this in "Ensure full NEON debug support" in
> https://wiki.linaro.org/WorkingGroups/KernelConsolidation/Specs/BSPInvestig…
> Any progress on this piece of work? We want to handle NEON registers in
> corefiles from GDB, which required kernel dump them in corefile first.
Hmmm, actually that bullet may have ended up in the wrong place ...
since it's not a BSP-specific feature.
Anyway, looking at the kernel code, it looks like the VFP/NEON state
is not dumped into the core file. If it makes you feel better, the
state of the obsolete FPE extension registers is dumped, if used :/
My guess is that it shouldn't be hard to dump the VFP/NEON state, but
GDB and the kernel need to agree on the format.
Rather that trying to hack the existing register dump format in a
compatible way, I suggest it's simplest if the kernel creates an extra
section in the dump containing something like:
.long format_version /* reserved for future expansion - must be 0 */
.long FPSID
.long FPSCR
.long MVFR0 /* or 0 if not present in the hardware */
.long MVFR1 /* or 0 if not present in the hardware */
.long d0
.long d1
/* ... d2-d14 ... */
.long d15
If 32 D-registers in the hardware [
.long d16
.long d17
/* ... d18-d30 ... */
.long d31
]
I believe we don't need any extra flags to indicate whether the MVFRx
fields are valid, since 0 in these registers indicates the
VFPv2/legacy behaviour anyway. Note that some VFPv2 implementations
(such as ARM1176) do provide these registers, and where the hardware
has them, the kernel can fill them in when doing the coredump.
We _should_ be prepared to ignore these fields (or interpret them
differently) if a vendor-specific VFP subarchitecture is specified (by
(FPSID & 0x4000) == 0x4000)
The number of D-registers can be deduced from the FPSID and MVFRx
registers, so we don't need to record it explicitly.
When MVFRx are not present, there are 16 D-registers.
When MVFRx are present, and (MVFR0 & 0xF) >= 2, there are 32 (or more)
D-registers
This is just a sketch -- the ARM ARM is the authoritative reference on
the meanings of these bitfields.
Any views on this?
Cheers
---Dave
>
> _______________________________________________
> linaro-dev mailing list
> linaro-dev(a)lists.linaro.org
> http://lists.linaro.org/mailman/listinfo/linaro-dev
>
== GCC ==
* Tracked down root cause of GCC mainline bootstrap failure
on ARM (PR 46040 - "__DTOR_LIST__ undeclared").
== Miscellaneous ==
* Set up IGEP v2 board (w/ local disk, network, ...) as
native GCC / GDB build environment.
* Gave talk on Linaro at the "2010 Linux Community Event" at
Siemens Munich (w/ Arnd Bergmann).
Mit freundlichen Gruessen / Best Regards
Ulrich Weigand
--
Dr. Ulrich Weigand | Phone: +49-7031/16-3727
STSM, GNU compiler and toolchain for Linux on System z and Cell/B.E.
IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Martin Jetter | Geschäftsführung: Dirk
Wittkopp
Sitz der Gesellschaft: Böblingen | Registergericht: Amtsgericht
Stuttgart, HRB 243294
You have been invited to the following event.
Title: TWG GCC Optimization
Discuss ideas for improving GCC optimization for ARM. Open to anybody who
wants to contribute.
https://wiki.linaro.org/AndrewStubbs/Sandbox/GCCoptimizations
International: +44 1452 567 588
UK: 0844 493 3801
Brazil: 08008912092
China: 108007121533
India: 0008001006354
Taiwan: 00801126472
United States: 18666161738
Conference code 2634417169#
When: Wed 2010-12-15 9am – 10am London
Where: Conference call code 263 441 7169
Calendar: linaro-toolchain(a)lists.linaro.org
Who:
* andrew.stubbs(a)linaro.org - creator
* Ken Werner - optional
* stevenb.gcc(a)gmail.com - optional
* Michael Hope - optional
* David Gilbert - optional
* Peter Maydell - optional
* ulrich.weigand(a)de.ibm.com - optional
* Yao Qi - optional
* Julian Brown - optional
* paul(a)codesourcery.com - optional
* Ira Rosen - optional
* richard.earnshaw(a)arm.com - optional
* Chung-Lin Tang - optional
* mark(a)codesourcery.com - optional
* linaro-toolchain(a)lists.linaro.org - optional
* Richard Sandiford - optional
* Marcin Juszkiewicz - optional
* zwelch(a)codesourcery.com - optional
Your attendance is optional.
Event details:
https://www.google.com/calendar/event?action=VIEW&eid=aXJlc2Z2bWZmZzQ5cGQ4b…
Invitation from Google Calendar: https://www.google.com/calendar/
You are receiving this courtesy email at the account
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To stop receiving future notifications for this event, decline this event.
Alternatively you can sign up for a Google account at
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your entire calendar.
== GCC related ==
* PR44557, Thumb-1 ICE: found two small needed corrections in the ARM
backend to fix this. Sent patch upstream.
* LP:641397/PR46888: bitfield insert optimization. Posted patch along
with Andrew Stubbs' CSE patch upstream. The two-patch situation seemed
to stir some discussion :) It seems both patches were deemed okay,
though it would be better if there was some testcase that passed through
unhandled by Andrew's CSE patch, but processed by my combine fix later
in the pass pipeline. Both patches queued at GCC bugzilla page, to be
handled in the next stage1.
* LP:687406/PR46865, -save-temps creating different code. Analyzed
problem, though slow to send fix upstream. Had some discussion on the
list on how the fix should be like.
* PR46667, section type conflicts. Tested and sent mail to gcc-patches.
Jan Hubicka picked it up and pinged for an approval again. Hope this get
resolved soon.
* PR45416, ARM code regression. ARM considerations are mostly okay, main
issue remaining is how to solve the x86 regression. The current expand
code does a full DImode shift just to obtain a single bit, might be
point of improvement to solve this.
* LP:685534, ftbfs with gcc-linaro 4.5 on amd64. Found to be another
erroneous inline asm case. Fixed and updated on LP.
== This week ==
* More upstream and Linaro GCC issues.
* Start dealing with January travel.
* Think more about larger (Linaro) GCC optimization projects.
== Linaro GDB ==
* LP:616000 Handle -fstack-protector prologue code
Understand how frame affect expression validation in GDB. Improve i386
prologue parsing to handle 'and/add' sequence. Revise i386 prologue
parsing for stack protector. Patch is not submitted since still lack of
i386 prologue knowledge, and not very confident on that patch.
Understand prologue-value used in ARM prologue parsing and relationship
of symbol and frame in GDB. Make ARM prologue parsing understands stack
protector code by identify the code sequence. Improve the patch by
supporting ARM mode and ARMv5T, in order to make this patch accepted by
upstreams.
* LP:615972 gdb.base/gcore.exp failure.
The failure is about "corefile restored general registers", which is not
related to NEON register support in corefile. It is caused by
inconsistent register types and names between tdesc and arm. The cause
of this failure is found, but upstreams reviewer doesn't agree on one of
my fix. As he suggested, arm-core.xml is modified to add "type=XXX",
but get some errors when regenerate arm-with-iwmmxt.c. Filed GDB PR 12308.
== GCC ==
* register rename improvements (LP:633243)
Finally, got both middle-end part and ARM part approved. Committed to
upstreams mainline. Some benchmarks in EEMBC shows 0.1%~0.2% code size
reduction.
== This Week ==
* Ping my GDB patches.
* Fix GDB PR 12308, which blocks my fix for LP:615972.
* Backport my approved patches to Linaro GDB if any. Fix other GDB bugs.
* Pass one GCC patch in my queue to review, if I have extra time.
== Vacation ==
Take vacation on Dec 30th and 31st. Travel to ChengDu, and back on 3rd
Jan (It is public holiday in China). Back to work on 4th Jan.
--
Yao (齐尧)
== This week ==
* Away Monday and Tuesday.
* Very little the rest of the week due to other IBM commitments.
I've just finished the main part of that work, so all being well,
it should only need a bit of nannying next week. Most of the week
should be Linaro.
* Started trying to reproduce #641126, but realised that I'd need
to set myself up for general Ubuntu cross package building first.
Started to look at what's involved.
== Next week ==
* Get stuck into #641126.
* More STT_GNU_IFUNC and vectors.
Richard