QtWebengine build error with opus and silk codecs

[Kart]

@SGaist Is it necessary to have neon support in the chip architecture to compile and run qtwebengine or for these codecs ?
How can I avoid using neon in the build ?

[SGaist]

I don't know, but I don't think so but thumb instructions have several advantages that are pretty interesting in the embedded world. You should rather consider enabling it.

[Kart]

@SGaist AFAIK, emulating neon in software will bring performance loss. My particular CPU hardware does not support neon and thereby, isn't it safe to disable it then ?
My CPU (cortex a9) does not support neon nor does the compiler.
-print-multi-lib gives

armv5te_arm9;@mcpu=arm926ej-s
a9;@mcpu=cortex-a9
a7;@mcpu=cortex-a7
armv5te_arm9_soft;@mcpu=arm926ej-s@mfloat-abi=soft
armv5te_arm9_vfp;@mcpu=arm926ej-s@mfloat-abi=softfp@mfpu=vfp
a9_soft;@mcpu=cortex-a9@mfloat-abi=soft
a9_softfp_vfp;@mcpu=cortex-a9@mfloat-abi=softfp@mfpu=vfp
a9_softfp_vfpv3-d16;@mcpu=cortex-a9@mfloat-abi=softfp@mfpu=vfpv3-d16
a7_soft;@mcpu=cortex-a7@mfloat-abi=soft
a7_softfp_vfpv4;@mcpu=cortex-a7@mfloat-abi=softfp@mfpu=vfpv4
a7_softfp_neon-vfpv4;@mcpu=cortex-a7@mfloat-abi=softfp@mfpu=neon-vfpv4
a7_hard_neon-vfpv4;@mcpu=cortex-a7@mfloat-abi=hard@mfpu=neon-vfpv4

I am stuck with this error now

libxxxx.a(yyyyy.o) uses VFP register arguments, libQt5WebEngineCore.so.5.9.1 does not

[SGaist]

Then you should create your own mkspecs that sets the correct flags for your processor.

[Kart]

@SGaist I am using my own qmake.conf.

#
# qmake configuration for building with arm400-linux-g++
#

MAKEFILE_GENERATOR      = UNIX
CONFIG                 += incremental
QMAKE_INCREMENTAL_STYLE = sublib


include(../common/linux.conf)
include(../common/gcc-base-unix.conf)
include(../common/g++-unix.conf)

# modifications to g++.conf
QMAKE_INCDIR +=/opt/arm400-linux/target/usr/include 
QMAKE_LIBDIR +=/opt/arm400-linux/target/usr/lib
QMAKE_CC                = arm400-linux-gcc 
QMAKE_CXX               = arm400-linux-g++
QMAKE_LINK              = arm400-linux-g++ -L/opt/arm400-linux/target/usr/lib -Wl,-rpath -Wl,/opt/arm400-linux/target/usr/lib
QMAKE_LINK_SHLIB        = arm400-linux-g++ -L/opt/arm400-linux/target/usr/lib -Wl,-rpath -Wl,/opt/arm400-linux/target/usr/lib

QMAKE_CFLAGS_RELEASE += -march=armv7-a -mcpu=cortex-a9
QMAKE_CXXFLAGS_RELEASE += -march=armv7-a -mcpu=cortex-a9

# modifications to linux.conf
QMAKE_AR                = arm400-linux-ar cqs
QMAKE_OBJCOPY           = arm400-linux-objcopy
QMAKE_STRIP             = arm400-linux-strip

load(qt_config)

I tried

QMAKE_CFLAGS_RELEASE += -march=armv7-a -mcpu=cortex-a9 -mfloat-abi=soft
QMAKE_CXXFLAGS_RELEASE += -march=armv7-a -mcpu=cortex-a9 -mfloat-abi=soft

But it came out something like "arm400-linux-g++: error: -mfloat-abi=soft and -mfloat-abi=hard may not be used together".

[SGaist]

From the looks of it, your system looks like the linux-tegra2-g++ mkspec, maybe this one will be more suited to copy from.

[Kart]

@SGaist
I have tried all these combinations

-mcpu=cortex-a9 -mfloat-abi=softfp -mfpu=vfp

-mcpu=cortex-a9 -mfloat-abi=softfp -mfpu=vfpv3-d16

-mtune=cortex-a9 -march=armv7-a -mhard-float -mfloat-abi=softfp 
-mfpu=vfpv3-d16

and i got the same error

libxxxx.a(yyyyy.o) uses VFP register arguments, libQt5WebEngineCore.so.5.9.1 does not

I tried the tegra2 mkspecs, but again another error.

ERROR at //build/config/android/internal_rules.gni:11:1: Assertion failed.
assert(is_android)
^-----
See //build/config/android/rules.gni:8:1: whence it was imported.
import("//build/config/android/internal_rules.gni")
^-------------------------------------------------
See //third_party/android_tools/BUILD.gn:5:1: whence it was imported.
import("//build/config/android/rules.gni")
^----------------------------------------
See //third_party/openmax_dl/dl/BUILD.gn:199:16: which caused the file to be included.
      deps = [ "//third_party/android_tools:cpu_features" ]
               ^-----------------------------------------
Project ERROR: GN run error!
Makefile:80: recipe for target 'sub-gn_run-pro-make_first' failed
make[3]: *** [sub-gn_run-pro-make_first] Error 3
make[3]: Leaving directory '/opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.2/qtwebengine/src/core'
Makefile:77: recipe for target 'sub-core-make_first' failed
make[2]: *** [sub-core-make_first] Error 2
make[2]: Leaving directory '/opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.2/qtwebengine/src'
Makefile:46: recipe for target 'sub-src-make_first' failed
make[1]: *** [sub-src-make_first] Error 2
make[1]: Leaving directory '/opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.2/qtwebengine'
Makefile:834: recipe for target 'module-qtwebengine-make_first' failed
make: *** [module-qtwebengine-make_first] Error 2

[SGaist]

Might be a silly question but did you nuke properly the build folder between tries ?

[Kart]

@SGaist I am deleting the source folder and doing all the steps from the beginning each and everytime.

[SGaist]

Ok, so when you said you tried the Tegra2 mkspec, did you just use it or did you copy from it into yours like I suggested ?

[Kart]

@SGaist This is how i used it.

include(../common/linux_device_pre.conf)

QMAKE_INCDIR_POST      += $$[QT_SYSROOT]/usr/include

QMAKE_LIBDIR_POST      += $$[QT_SYSROOT]/usr/lib

QMAKE_RPATHLINKDIR_POST += $$[QT_SYSROOT]/usr/lib

QMAKE_CFLAGS           += -mtune=cortex-a9 -march=armv7-a -mhard-float -mfloat-abi=softfp -mfpu=vfpv3-d16
QMAKE_CXXFLAGS         += -mtune=cortex-a9 -march=armv7-a -mhard-float -mfloat-abi=softfp -mfpu=vfpv3-d16

include(../common/linux_arm_device_post.conf)

load(qt_config)

This is my qmake.conf.

[Kart]

Does anyone knows how ninja build in qtwebengine is getting these architecture values by default ?

-mfloat-abi=hard -mtune=generic-armv7-a -mfpu=vfpv3-d16 -mthumb

[SGaist]

From a quick look, somewhere around:

src/3rdparty/chromium/breakpad/src/build/common.gypi
src/3rdparty/chromium/build/config/compiler/BUILD.gn
src/3rdparty/chromium/build/common.gypi
src/3rdparty/chromium/native_client/build/standalone_flags.gypi
src/3rdparty/chromium/native_client/build/untrusted.gypi
./src/core/config/linux.pri:    MFLOAT = $$extractCFlag("-mfloat-abi=.*")

[Kart]

Thanks @SGaist. This file had some information. I am not sure with the syntax to make changes in this file.

./src/core/config/linux.pri:    MFLOAT = $$extractCFlag("-mfloat-abi=.*")

Whatever values I am giving to QMAKE_CFLAGS_RELEASE and QMAKE_CXXXFLAGS_RELEASE is not what GN build is taking.

Maybe if I figure out how to make changes in the file you have mentioned, I might be able to solve this issue.

[Kart]

In the file

qtwebengine/src/3rdparty/chromium/third_party/opus/BUILD.gn:     use_opus_rtcd = current_cpu == "arm" && (is_win || is_android || is_linux)

qtwebengine/src/3rdparty/chromium/third_party/opus/BUILD.gn: 
 if (use_opus_rtcd) {
      sources += [
        "$target_gen_dir/celt_pitch_xcorr_arm_gnu.S",
        "src/celt/arm/arm_celt_map.c",
        "src/celt/arm/armcpu.c",
        "src/celt/arm/armcpu.h",
        "src/celt/arm/celt_neon_intr.c",
        "src/celt/arm/fft_arm.h",
        "src/celt/arm/mdct_arm.h",
        "src/celt/arm/pitch_arm.h",
        "src/silk/arm/NSQ_neon.c",
        "src/silk/arm/NSQ_neon.h",
        "src/silk/arm/arm_silk_map.c",
      ]

As far as I understood if the CPU is based on ARM and the OS is linux use_opus_rtcd becomes TRUE. If it becomes true, qtwebengine/src/3rdparty/chromium/third_party/opus/src/celt/arm/armcpu.c decides whether it have the NEON capabilities. I am trying to see that changing armcpu.c to not to use NEON might work or not.

[Torsten Krause]

The chromium snapshot is outdated. There is already a fix for that!

link text