On Thu, Mar 31, 2016 at 5:12 AM, fengwei.yin <fengwei.yin(a)linaro.org> wrote:
> Because gcc 4.9 could build this file without any issue, I apply
> --save-temps
> with gcc 4.9. The ii file is attached. Can't see significant differences.
There is a patch in gcc-5 to make unified assembler syntax the
default. Unfortunately, it changes how extended asms work, which is
perhaps a bug. The message claims it doesn't affect extended asms,
but it does.
https://gcc.gnu.org/ml/gcc-patches/2015-11/msg01196.html
The interesting bit is the change to ASM_APP_OFF.
gcc-4.9 emits a .thumb after the extended asm to switch back into
thumb mode just in case. gcc-5.3 instead emits .syntax unified, which
doesn't change the arm/thumb mode, just the syntax supported. This is
arguably a bug, but this doesn't immediately help you. It could take
a little time to get gcc-5.x source fixed, and then the compiler
binary releases. Or alternatively we could fix the asm to work with
gcc 5.
Jim
== Progress ==
o Extended validation (7/10)
* Fixed and improved extended native validation
* Discussed proposed patch in dejagnu on process killing mechanism
* Testing a fix/workaround in GCC guality tests
* Re-implemented and tested fix for dejagnu remote layout
o Misc (3/10)
* Various meetings
== Plan ==
o Continue on extended validation
o Finalize DejaGNU patches, GCC ARMv8.1 builtins fix.
== This week ==
* Bugzilla 69008 - gcc emits unneeded memory access when passing trivial
structs by value (ARM) (3/10)
- Additional investigation and preliminary implementation
* Bugzilla 70089 - ARM/THUMB unnecessarily typecasts some rvalues on
memory store (1/10)
- Investigation
* TCWG-247 - Create Validation Job to run on GCC Trunk Committ (5/10)
- Began writing shell script.
* Misc meeting (1/10)
== Next week ==
* TCWG-247
- Make additional prgoress on prototype
* Bugzilla 69008 - gcc emits unneeded memory access when passing trivial
structs by value (ARM)
- Additional investigation and preliminary implementation
* Bugzilla 70089 - ARM/THUMB unnecessarily typecasts some rvalues on
memory store
- Investigation
* Vacation
- April 8 - April 12
== Progress ==
* Holiday (2/10)
* Support (1/10)
- Reapplying fix for PR16275 (D18701)
- Conclusion is that original approach will be the same as GCC
- Additional flags will have to be agreed upon across compilers
* Buildbot (2/10)
- Setting up LLDB buildbot with Omair
- Precarious infrastructure is unstable, hope it holds on until the
new rack is complete
* Background (5/10)
- Code review, meetings, discussions, general support, etc.
- More team management stuff (access/procedure/meeting with newcomers)
- Planning the lab move, resources, costs, schedule
* Monday off [2/10]
# Progress #
* TCWG-167, ARM reverse debugging bug fixes. [4/10]
Two patches are posted. Two patches are being tested. They fix
207 FAILs (242 -> 35) in gdb.reverse.
* TCWG-545, no progress, patches are pending for review.
* TCWG-547, [2/10]. Write a patch as Pedro suggested, so we have
sense which patch is better. No response.
* Misc, [2/10]
** Upstream discussions on get syscall number on execve exit. Can't
get such thing from kernel side, need to figure out how to do it
in GDB side.
** Investigate a little bit on 32-bit DWARF on AArch64.
# Plan #
* TCWG-167, TCWG-545, TCWG-547
--
Yao
== This Week ==
* LTO (7/10)
a) TCWG-534 (ipa-comdats):
- Patch posted upstream: https://gcc.gnu.org/ml/gcc/2016-03/msg00254.html
- Investigating ICE with patch for comdat-2.C
b) TCWG-128 (branch out of range error):
- Posted patch upstream:
https://gcc.gnu.org/ml/gcc-patches/2016-04/msg00032.html
c) intra-procedural vrp:
- Looking to implement replacement_order algorithm for early vrp from the paper:
https://engineering.purdue.edu/paramnt/publications/1381.pdf
* Validation (2/10)
- Reviews on tcwg-buildapp from Christophe and Maxim
- prototype job ran successfully.
* Misc (1/10)
- Meetings
== Next Week ==
* LTO:
- Try to implement replacement order algorithm for vrp
- Continue investigating ipa-comdats ICE and address upstream comments.
- Gather stats for chromium LTO build
* Validation:
- write script to build chromium
On Wed, Mar 30, 2016 at 6:26 PM, fengwei.yin <fengwei.yin(a)linaro.org> wrote:
> Thanks a lot for your quick response. The .ii file was attached.
In UnwindFromContext, there is an asm that forces the assembler into ARM mode.
if (ucontext == nullptr) {
int ret = (({ unw_tdep_context_t *unw_ctx = (&context_); register unsigned \
long *unw_base asm ("r0") = unw_ctx->regs; __asm__ __volatile__ ( ".align 2\nbx\
pc\nnop\n.code 32\n" "stmia %[base], {r0-r15}\n" "orr %[base], pc, #1\nbx %[ba\
se]" : [base] "+r" (unw_base) : : "memory", "cc"); }), 0);
The ".code 32" puts us in ARM mode.
GCC still thinks that we are in thumb mode though, and continues to
emit thumb instructions, some of which have no arm mode equivalent,
e.g. cbnz and cbz.
I don't see any convenient push/pop for thumb/arm mode. This is
probably a macro expanded into the asm. You could have two versions
of the asm, one that gets used when __thumb__ is defined and one that
gets used when __thumb__ is not defined. The __thumb__ version would
switch back into thumb mode at the end with a ".thumb" pseudo-op.
Or alternatively, don't build with -mthumb.
Jim
Hi folks,
I am trying to use arm gcc 5.3 to build part of android AOSP and hit
following issue with arm gcc 5.3:
The gcc cmd line is like:
/opt/work/acadine/mem_shrink/B2G-v2.5/prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-5.3-linaro/bin/arm-linux-androideabi-g++
-I external/libcxx/include -I system/core/libbacktrace -I
out/target/product/linaro_arm/obj/SHARED_LIBRARIES/libbacktrace_intermediates
-I
out/target/product/linaro_arm/gen/SHARED_LIBRARIES/libbacktrace_intermediates
-I libnativehelper/include/nativehelper -I system/core/base/include -I
external/libunwind/include -isystem system/core/include -isystem
system/media/audio/include -isystem hardware/libhardware/include
-isystem hardware/libhardware_legacy/include -isystem
hardware/ril/include -isystem libnativehelper/include -isystem
frameworks/native/include -isystem frameworks/native/opengl/include
-isystem frameworks/av/include -isystem frameworks/base/include -isystem
out/target/product/linaro_arm/obj/include -isystem
bionic/libc/arch-arm/include -isystem bionic/libc/include -isystem
bionic/libc/kernel/uapi -isystem bionic/libc/kernel/uapi/asm-arm
-isystem bionic/libm/include -isystem bionic/libm/include/arm -c
-fno-exceptions -Wno-multichar -msoft-float -ffunction-sections
-fdata-sections -funwind-tables -fstack-protector -Wa,--noexecstack
-Werror=format-security -D_FORTIFY_SOURCE=2 -fno-short-enums
-no-canonical-prefixes -fno-canonical-system-headers -march=armv7-a
-mfloat-abi=softfp -mfpu=vfpv3-d16 -include
build/core/combo/include/arch/linux-arm/AndroidConfig.h -I
build/core/combo/include/arch/linux-arm/ -Wno-psabi -mthumb-interwork
-DANDROID -fmessage-length=0 -W -Wall -Wno-unused -Winit-self
-Wpointer-arith -Werror=return-type -Werror=non-virtual-dtor
-Werror=address -Werror=sequence-point -DNDEBUG -g -Wstrict-aliasing=2
-fgcse-after-reload -frerun-cse-after-loop -frename-registers -DNDEBUG
-UDEBUG -fvisibility-inlines-hidden -DANDROID -fmessage-length=0 -W
-Wall -Wno-unused -Winit-self -Wpointer-arith -Wsign-promo -std=gnu++11
-Werror=return-type -Werror=non-virtual-dtor -Werror=address
-Werror=sequence-point -DNDEBUG -UDEBUG -mthumb -Os -fomit-frame-pointer
-fno-strict-aliasing -fno-rtti -Wall -Werror -fPIC -D_USING_LIBCXX
-std=gnu++11 -Werror=int-to-pointer-cast
-Werror=pointer-to-int-cast -MD -MF
out/target/product/linaro_arm/obj/SHARED_LIBRARIES/libbacktrace_intermediates/UnwindCurrent.d
-o
out/target/product/linaro_arm/obj/SHARED_LIBRARIES/libbacktrace_intermediates/UnwindCurrent.o
system/core/libbacktrace/UnwindCurrent.cpp
And I got error:
/tmp/ccZ40ViQ.s: Assembler messages:
/tmp/ccZ40ViQ.s:1752: Error: selected processor does not support ARM
mode `cbnz r6,.L91'
/tmp/ccZ40ViQ.s:1758: Error: selected processor does not support ARM
mode `cbnz r0,.L92'
/tmp/ccZ40ViQ.s:1763: Error: selected processor does not support ARM
mode `cbz r1,.L107'
/tmp/ccZ40ViQ.s:1941: Error: selected processor does not support ARM
mode `cbz r6,.L100'
But if I use the arm gcc 4.9, there is no any build issue.
the "-dumpspecs" output of gcc 5.3 was attached. Thanks.
Regards
Yin, Fengwei
