[graysky]

I am building kodi on Arch ARM for Raspberry Pi2 (armv7h) with the following this cmake stanza. It works but it throws tons of warnings about conflicting switches. For example:

Code:

/scratch-nfs/PKGBUILDs/alarm/kodi-rbp/src/xbmc-17.3-Krypton/xbmc/profiles/ProfilesManager.cpp:1:0: warning: switch -mcpu=cortex-a7 conflicts with -march=armv7-a switch
...
/scratch-nfs/PKGBUILDs/alarm/kodi-rbp/src/xbmc-17.3-Krypton/xbmc/interfaces/legacy/WindowXML.cpp:1:0: warning: switch -mcpu=cortex-a7 conflicts with -march=armv7-a switch

The CFLAGS and CXXFLAGS are the distro default. Should I adjust the -DWITH_CPU flag to something else? The resulting package should run on both RPi2 and RPi3. Thanks.

Code:

export CFLAGS="-march=armv7-a -mfloat-abi=hard -mfpu=vfpv3-d16 -O2 -pipe -fstack-protector --param=ssp-buffer-size=4"
export CXXFLAGS="-march=armv7-a -mfloat-abi=hard -mfpu=vfpv3-d16 -O2 -pipe -fstack-protector --param=ssp-buffer-size=4"

cmake -DCMAKE_INSTALL_PREFIX=/usr \
-DCMAKE_INSTALL_LIBDIR=/usr/lib \
-DCMAKE_PREFIX_PATH=/opt/vc \
-DCORE_SYSTEM_NAME=rbpi \
-DWITH_CPU=cortex-a7 \
-DENABLE_EVENTCLIENTS=ON \
-DENABLE_OPENGL=OFF \
-DENABLE_X11=OFF \
-DENABLE_VAAPI=OFF \
-DENABLE_VDPAU=OFF \
-DLIRC_DEVICE=/run/lirc/lircd \
../xbmc-17.3-Krypton/project/cmake

make
make preinstall

[asavah]

The warning is correct,
the right march for cortex-a7 is armv7ve

If you're building on/for pi2 mfpu is wrong too,
should be neon-vfpv4

[graysky]

The warning is correct,
the right march for cortex-a7 is armv7ve

If you're building on/for pi2 mfpu is wrong too,
should be neon-vfpv4

I found this bug report that agrees with your march statement.... yet:

Code:

% gcc -c -Q -march=native --help=target | grep march        
  -march=                             armv7-a

EDIT: Also looking in tools/depends/configure.ac it seems that they are hardcoding the values I picked. Perhaps I am misunderstanding?

[asavah]

Yep, it,s hardcoded there, but that's correct for pi2 and the warning comes from c*flags in pkgbuild.
As for the other part - can't tell, it's actually gcc internals, which is complicated stuff, my pi2 has an old build of my crappo-os without gcc, can't check.

EDIT: I think the march stuff changed between gcc versions, eg armv7-a was ok for 5.x and lower, but changed for 6.x and higher,
I currently use linaro-7.1

[graysky]

After some tinkering, I ended up modifying the C*LAGS in the PKGBUILD which removed the warnings.

Code:

CFLAGS+=" -march=armv7ve"
  CXXFLAGS="${CFLAGS}"

  cmake -DCMAKE_INSTALL_PREFIX=/usr \
    -DCMAKE_INSTALL_LIBDIR=/usr/lib \
    -DENABLE_EVENTCLIENTS=ON \
    -DLIRC_DEVICE=/run/lirc/lircd \
    -DWITH_CPU=cortex-a7 \
    -DENABLE_CEC=OFF \
    -DENABLE_SSH=OFF \
    -DCMAKE_PREFIX_PATH=/opt/vc \
    -DCORE_SYSTEM_NAME=rbpi \
    -DENABLE_OPENGL=OFF \
    -DENABLE_X11=OFF \
    -DENABLE_VAAPI=OFF \
    -DENABLE_VDPAU=OFF \
    ../"xbmc-$pkgver-$_codename"/project/cmake
...

[graysky]

The warning is correct,
the right march for cortex-a7 is armv7ve

 Old thread but relevant question: how did you make the association between cortex-a7 and armv7ve?  I ask because I see a similar warning when I build for the original RPi (armv6h):

Code:

cc1: warning: switch -mcpu=arm1176jzf-s conflicts with -march=armv6 switch

I'm seeking the correct value for -march= for armv6h for RPi1.  Thanks!

EDIT:  Seems like the setting might be armv6zk:

Code:

%  gcc -c -Q -march=native --help=target       
The following options are target specific:
  -mabi=                              aapcs-linux
  -mabort-on-noreturn                 [disabled]
  -mandroid                           [disabled]
  -mapcs                              [disabled]
  -mapcs-frame                        [disabled]
  -mapcs-reentrant                    [disabled]
  -mapcs-stack-check                  [disabled]
  -march=                             armv6zk
  -marm                               [enabled]
  -masm-syntax-unified                [disabled]
  -mbig-endian                        [disabled]
  -mbionic                            [disabled]
  -mcallee-super-interworking         [disabled]
  -mcaller-super-interworking         [disabled]
  -mcmse                              [disabled]
  -mcpu=                              [default]
  -mfix-cortex-m3-ldrd                [disabled]
  -mflip-thumb                        [disabled]
  -mfloat-abi=                        hard
  -mfp16-format=                      none
  -mfpu=                              vfp
  -mglibc                             [enabled]
  -mhard-float                        
  -mlittle-endian                     [enabled]
  -mlong-calls                        [disabled]
  -mmusl                              [disabled]
  -mneon-for-64bits                   [disabled]
  -mpic-data-is-text-relative         [enabled]
  -mpic-register=                     
  -mpoke-function-name                [disabled]
  -mprint-tune-info                   [disabled]
  -mpure-code                         [disabled]
  -mrestrict-it                       [disabled]
  -msched-prolog                      [enabled]
  -msingle-pic-base                   [disabled]
  -mslow-flash-data                   [disabled]
  -msoft-float                        
  -mstructure-size-boundary=          8
  -mthumb                             [disabled]
  -mthumb-interwork                   [disabled]
  -mtls-dialect=                      gnu
  -mtp=                               cp15
  -mtpcs-frame                        [disabled]
  -mtpcs-leaf-frame                   [disabled]
  -mtune=                             [default]
  -muclibc                            [disabled]
  -munaligned-access                  [enabled]
  -mvectorize-with-neon-double         [disabled]
  -mvectorize-with-neon-quad          [enabled]
  -mword-relocations                  [disabled]

  Known ARM ABIs (for use with the -mabi= option):
    aapcs aapcs-linux apcs-gnu atpcs iwmmxt

  Known ARM architectures (for use with the -march= option):
    armv2 armv2a armv3 armv3m armv4 armv4t armv5 armv5e armv5t armv5te armv5tej armv6 armv6-m armv6j armv6k armv6kz armv6s-m
    armv6t2 armv6z armv6zk armv7 armv7-a armv7-m armv7-r armv7e-m armv7ve armv8-a armv8-a+crc armv8-m.base armv8-m.main
    armv8-m.main+dsp armv8.1-a armv8.2-a armv8.2-a+fp16 iwmmxt iwmmxt2 native

  Known __fp16 formats (for use with the -mfp16-format= option):
    alternative ieee none

  Known ARM FPUs (for use with the -mfpu= option):
    auto crypto-neon-fp-armv8 fp-armv8 fpv4-sp-d16 fpv5-d16 fpv5-sp-d16 neon neon-fp-armv8 neon-fp16 neon-vfpv3 neon-vfpv4 vfp
    vfp3 vfpv2 vfpv3 vfpv3-d16 vfpv3-d16-fp16 vfpv3-fp16 vfpv3xd vfpv3xd-fp16 vfpv4 vfpv4-d16

  Valid arguments to -mtp=:
    auto cp15 soft

  Known floating-point ABIs (for use with the -mfloat-abi= option):
    hard soft softfp

  Known ARM CPUs (for use with the -mcpu= and -mtune= options):
    arm1020e arm1020t arm1022e arm1026ej-s arm10e arm10tdmi arm1136j-s arm1136jf-s arm1156t2-s arm1156t2f-s arm1176jz-s
    arm1176jzf-s arm2 arm250 arm3 arm6 arm60 arm600 arm610 arm620 arm7 arm70 arm700 arm700i arm710 arm7100 arm710c arm710t
    arm720 arm720t arm740t arm7500 arm7500fe arm7d arm7di arm7dm arm7dmi arm7m arm7tdmi arm7tdmi-s arm8 arm810 arm9 arm920
    arm920t arm922t arm926ej-s arm940t arm946e-s arm966e-s arm968e-s arm9e arm9tdmi cortex-a12 cortex-a15 cortex-a15.cortex-a7
    cortex-a17 cortex-a17.cortex-a7 cortex-a32 cortex-a35 cortex-a5 cortex-a53 cortex-a57 cortex-a57.cortex-a53 cortex-a7
    cortex-a72 cortex-a72.cortex-a53 cortex-a73 cortex-a73.cortex-a35 cortex-a73.cortex-a53 cortex-a8 cortex-a9 cortex-m0
    cortex-m0.small-multiply cortex-m0plus cortex-m0plus.small-multiply cortex-m1 cortex-m1.small-multiply cortex-m23 cortex-m3
    cortex-m33 cortex-m4 cortex-m7 cortex-r4 cortex-r4f cortex-r5 cortex-r7 cortex-r8 ep9312 exynos-m1 fa526 fa606te fa626
    fa626te fa726te fmp626 generic-armv7-a iwmmxt iwmmxt2 marvell-pj4 mpcore mpcorenovfp native strongarm strongarm110
    strongarm1100 strongarm1110 xgene1 xscale

  TLS dialect to use:
    gnu gnu2

[asavah]

Honestly I don't remember where I found the info, probably google, arm docs, gcc docs.
I use following cflags:

Code:


pi3: -mcpu=cortex-a53+crc -mfpu=neon-fp-armv8 <- yep, this is for 32bit
pi2: -mcpu=cortex-a7 -mfpu=neon-vfpv4
pi1: -mcpu=arm1176jzf-s -mfpu=vfp

For pi1 if my old notes don't lie march is -march=armv6zk
Note that if you set mcpu there is no need for march anymore, at least on modern gcc.

[graysky]

Note that if you set mcpu there is no need for march anymore, at least on modern gcc.

 Is that how it works?  I always thought one should define the -march= parameter and that would trigger other flags automatically.

On my RPi3:

Code:

% gcc -c -Q -march=native --help=target | grep 'march\|mtune\|mcpu\|mfpu'
  -march=                             armv8-a+crc
  -mcpu=                              [default]
  -mfpu=                              vfpv3-d16
  -mtune=                             [default]

So do the [default] values imply I need only set march and mfpu?

[asavah]

See https://gcc.gnu.org/onlinedocs/gcc-7.2.0...tions.html

As I understand it mcpu is a shortcut for both march and mtune, however -mfpu=vpfv3-d16 for pi 2 seems wrong to me,
see https://community.arm.com/tools/b/blog/p...mand-lines
and it may have been the cause of your crashes.

[graysky]

Thanks for the links... when I try building on my RPi3 (running Arch ARM armv7h) with your mcpu line, I kodi 17.6 fails:

Code:

-- The CXX compiler identification is GNU 7.2.1
-- The C compiler identification is GNU 7.2.1
-- The ASM compiler identification is GNU
-- Found assembler: /usr/lib/distcc/bin/cc
-- Check for working CXX compiler: /usr/lib/distcc/bin/c++
-- Check for working CXX compiler: /usr/lib/distcc/bin/c++ -- broken
CMake Error at /usr/share/cmake-3.10/Modules/CMakeTestCXXCompiler.cmake:45 (message):
  The C++ compiler

    "/usr/lib/distcc/bin/c++"

  is not able to compile a simple test program.

  It fails with the following output:

    Change Dir: /scratch/PKGBUILDs/alarm/kodi-rbp/src/kodi-build/CMakeFiles/CMakeTmp
    
    Run Build Command:"/usr/bin/make" "cmTC_9ab3a/fast"
    /usr/bin/make -f CMakeFiles/cmTC_9ab3a.dir/build.make CMakeFiles/cmTC_9ab3a.dir/build
    make[1]: Entering directory '/scratch/PKGBUILDs/alarm/kodi-rbp/src/kodi-build/CMakeFiles/CMakeTmp'
    Building CXX object CMakeFiles/cmTC_9ab3a.dir/testCXXCompiler.cxx.o
    /usr/lib/distcc/bin/c++    -march=armv7-a -mfloat-abi=hard -mfpu=vfpv3-d16 -O2 -pipe -fstack-protector-strong -fno-plt -march=armv8-a+crc -mfpu=neon-fp-armv8 -mcpu=cortex-a53+crc    -o CMakeFiles/cmTC_9ab3a.dir/testCXXCompiler.cxx.o -c /scratch/PKGBUILDs/alarm/kodi-rbp/src/kodi-build/CMakeFiles/CMakeTmp/testCXXCompiler.cxx
    distcc[18109] (dcc_build_somewhere) Warning: failed to distribute, running locally instead
    c++: error: unrecognized argument in option ‘-mcpu=cortex-a53+crc’
    c++: note: valid arguments to ‘-mcpu=’ are: arm1020e arm1020t arm1022e arm1026ej-s arm10e arm10tdmi arm1136j-s arm1136jf-s arm1156t2-s arm1156t2f-s arm1176jz-s arm1176jzf-s arm2 arm250 arm3 arm6 arm60 arm600 arm610 arm620 arm7 arm70 arm700 arm700i arm710 arm7100 arm710c arm710t arm720 arm720t arm740t arm7500 arm7500fe arm7d arm7di arm7dm arm7dmi arm7m arm7tdmi arm7tdmi-s arm8 arm810 arm9 arm920 arm920t arm922t arm926ej-s arm940t arm946e-s arm966e-s arm968e-s arm9e arm9tdmi cortex-a12 cortex-a15 cortex-a15.cortex-a7 cortex-a17 cortex-a17.cortex-a7 cortex-a32 cortex-a35 cortex-a5 cortex-a53 cortex-a57 cortex-a57.cortex-a53 cortex-a7 cortex-a72 cortex-a72.cortex-a53 cortex-a73 cortex-a73.cortex-a35 cortex-a73.cortex-a53 cortex-a8 cortex-a9 cortex-m0 cortex-m0.small-multiply cortex-m0plus cortex-m0plus.small-multiply cortex-m1 cortex-m1.small-multiply cortex-m23 cortex-m3 cortex-m33 cortex-m4 cortex-m7 cortex-r4 cortex-r4f cortex-r5 cortex-r7 cortex-r8 ep9312 exynos-m1 fa526 fa606te fa626 fa626te fa726te fmp626 generic-armv7-a iwmmxt iwmmxt2 marvell-pj4 mpcore mpcorenovfp native strongarm strongarm110 strongarm1100 strongarm1110 xgene1 xscale; did you mean ‘cortex-a53’?
    distcc[18109] ERROR: compile /scratch/PKGBUILDs/alarm/kodi-rbp/src/kodi-build/CMakeFiles/CMakeTmp/testCXXCompiler.cxx on localhost failed
    make[1]: *** [CMakeFiles/cmTC_9ab3a.dir/build.make:66: CMakeFiles/cmTC_9ab3a.dir/testCXXCompiler.cxx.o] Error 1
    make[1]: Leaving directory '/scratch/PKGBUILDs/alarm/kodi-rbp/src/kodi-build/CMakeFiles/CMakeTmp'
    make: *** [Makefile:126: cmTC_9ab3a/fast] Error 2
    

  

  CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
  CMakeLists.txt:2 (project)


-- Configuring incomplete, errors occurred!
See also "/scratch/PKGBUILDs/alarm/kodi-rbp/src/kodi-build/CMakeFiles/CMakeOutput.log".
See also "/scratch/PKGBUILDs/alarm/kodi-rbp/src/kodi-build/CMakeFiles/CMakeError.log".

Seems that my gcc doesn't recognize it as a valid option.  Arch ARM arm7h is currently shipping gcc (GCC) 7.2.1 20180116.

[asavah]

Ouch, drop the +crc part, I was writing from memory.
The flags you linked apply to depends, not sure if they are used for kodi itself,
AFAIK for building  kodi itself these https://github.com/xbmc/xbmc/blob/master....cmake#L24 are used.
But if other flags are present in the environment vars I'm not sure which ones will take precedence.

[graysky]

Also, don't the hard-coded "platform_cflags" in the following two files take over?  They seem to.... I defined -mcpu=cortex-a53 but during the build, cc throws me these warnings suggesting something redefined it:

Code:

cc1plus: warning: switch -mcpu=cortex-a7 conflicts with -march=armv8-a+crc switch

In grepping for cortex-a7 these are 2 likely suspects:
https://github.com/xbmc/xbmc/blob/Krypto...c#L403-409
https://github.com/xbmc/xbmc/blob/Krypto....cmake#L20

[graysky]

Got it!  So the Arch ARM (armv7h) default CFLAGS in /etc/makepkg.conf are:

Code:

CFLAGS="-march=armv7-a -mfloat-abi=hard -mfpu=vfpv3-d16 -O2 -pipe -fstack-protector-strong -fno-plt"

I redefined in the PKGBUILD with:

Code:

CFLAGS+=" -march=armv8-a+crc -mfpu=neon-fp-armv8 -mcpu=cortex-a53"

And I patched the source with the following to get the result I described:
https://github.com/graysky2/kodi-raspberrypi3