Hi,
- investigating detection of general over-widening cases in the vectorizer
- improvements of widen-mult - proposed for merge to gcc-linaro-4.6
- fixed PRs 49443 and 49478
Ira
Hi,
* in order to have the android's debuggerd use libunwind I looked at
libunwind's remote interface and especially the libunwind-ptrace lib
that sits on top of that.
* the remote interface seems a bit awkward to me. The user provides
a set of callbacks to access the inferior memory or registers. Instead
of using these callbacks to obtain the actual unwind information
(eh_frame fro example) it requires the user implement another callback
(find_proc_info) to lookup the unwind info himself.
* the libunwind-ptrace currently deos not support the ARM specific
unwind tables
* started to look into how to improve the situation
* not straight forward as it's tightly bound to eh_frame unw info
and libunwinds DWARF parsing mechanism
* attending a class this afternoon
* Note: I'm on vacation starting in a few hours and I'll be back on
Tuesday next week.
Regards
Ken
== Progress ==
* Backported A5 / A15 tuning to Linaro GCC. Waiting for test results.
* T2 perf. meeting.
* Backported the neon length patch back.
* Patch for PR49385 being tested.
* Bootstraps broken yet again / upstream maintenance / test regressions.
* Waiting on Branch_cost results .
* Minor binutils patches as a result of upstream maintenance.
== Plans ==
* Finish BRANCH_COST tuning
* Look at VFP moves for some more .
* Backport some of the upstream bug fixes that need to be done.
Meetings:
* 1-1s
* TCWG call.
* At Google unconference 17-19 June
Chaired the Toolchain Working group call. Michael H was unavailable (but
OK) following yet another earthquake in Christchurch.
Continued working on my widening multiplies patches. I did think for a
while there must be a logic flaw because it's using the wrong sized
inputs to instructions, but on closer inspection that was taken care of
in the RTL transformations. The changes I already had seem good in all
the test cases I could generate. I've also identified a number of
additional optimization opportunities, so I've been tweaking the patch
for those.
Continued trying to figure out why my Thumb2 constants patches break the
native bootstrap build. The stage2 compiler enters an infinite loop, but
I couldn't easily identify why, as yet.
Backported Julian's unaligned access patches to a Linaro test branch.
----
Upstream patched requiring review:
* NEON scheduling patch
http://gcc.gnu.org/ml/gcc-patches/2011-02/msg01431.html
== This week ==
* Experimented more with A8 and A9 tuning for auto inc/dec addresses.
* More work on the auto inc/dec pass itself.
* Compared the assembly output in the GCC testsuite for a range
of targets (avr, bfin, h8300, ia64, m32c, m32r, m68k, am33,
pa, pdp11, powerpc, rx, score, sh, xstormy16 and vax).
* Looked at a few bug reports. Will submit patches when I get back.
== Next week ==
* Holiday!
Richard
== 64 bit Atomics ==
* Wrote more test cases; now have a nice 3 thread test that passes -
and more importantly, it fails if I replace one of the atomic ops
by a non-atomic equivalent.
* Modified existing atomic helper code in libgcc to do 64bit
* Added init function to 64bit atomic helper to detect presence of
new kernel and fail if an old one is present.
That last one is a bit of a pain; it now correctly exits on existing
kernels and aborts; qemu user space seg faults
because access to the kernel helper version address is uncaught. So
first thing I need to do is try the early kernel patch Nicolas
sent around, and then I really need to see if qemu can be firmly
persuaded to run it.
== String routines ==
* Ran denbench with sets of strlen; started running some spec as well.
== QEmu ==
* Tested Peter's prelease tarball in user space and a bunch of
system emulations
- successfully managed to say hello to #linaro from an emulated
overo board using USB keyboard.
== Other ==
* Booked 4th July week off.
Dave
Hi,
* short week (Monday -> public holiday, Wednesday -> attended a class)
* tested the gcc-linaro-4.5-2011.06 with linaro-android on my panda
* works! no noticeable differences to 4.5-2011.05 for me
* libgui.so apriori prelink issue remains:
* realized that apriori works quite different from GNU prelink
* checked the prelink map against LOAD segment size - looks good
* build with -DLINKER_DEBUG=1 - still doesn't give hints
* give up for know and moving on
* made a patchset to be able to build whole android with -DDEBUG
* except of v8 and webkit
* zygote segfaults for unknown reason
* understood the basics of the current backtracing mechanism on android
* the bionic linker registers signal handlers on SIGSEGV that opens
a socket
* the debuggerd listens on that socket and gets its regs etc. using
ptrace
* Note: I'll be on vacation starting on Thursday next week
Regards
Ken
== GDB ==
* Committed support for NEON registers in core dumps (bug #615972)
to mainline GDB and binutils repositories.
* Added support to readelf (mainline binutils) to correctly display
NEON register core file notes.
* Started looking into remote gdb testsuite.
== GCC ==
* Investigated reload failure when building kernel with Linaro GCC 4.5
(discovered by Arnd).
* Investigated stray function references due to partial inlining
breaking kernel build with Linaro GCC 4.6 (discovered by Arnd).
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
Hi Michael,
This thread about how to generate ancillary sections using gas has
resurfaced again. Do you know who might be available from the
toolchain group to take a look at this?
It appears that this issue can best be solved by a change to gas
(or, possibly, to gcc).
Cheers
---Dave
References:
Dynamic patching in discarded sections
<http://thread.gmane.org/gmane.linux.kernel/1152142>
Generating ancilliary sections with gas
<http://thread.gmane.org/gmane.linux.linaro.toolchain/686>
