QtWebengine build error with opus and silk codecs

[Kart]

This is like my fourth or fifth post regarding QtWebengine. I am almost spaming the Qt forum i guess.
I am trying to build Qt5.91 with QtWebengine for an arm platform.
These are some architecture based arguments i am passing to the build.

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

By default the build is going these values as well.

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

Below is my configuration summary

Building on: linux-g++ (i386, CPU features: <none>)
Building for: linux-arm-g++ (arm, CPU features: <none>)
Configuration: cross_compile compile_examples enable_new_dtags largefile precompile_header shared rpath release c++11 concurrent dbus mremap reduce_exports stl
Build options:
  Mode ................................... release
  Optimize release build for size ........ no
  Building shared libraries .............. yes
  Using C++ standard ..................... C++11
  Using gold linker ...................... no
  Using new DTAGS ........................ yes
  Using precompiled headers .............. yes
  Using LTCG ............................. no
  Target compiler supports:
    NEON ................................. no
  Build parts ............................ libs
Qt modules and options:
  Qt Concurrent .......................... yes
  Qt D-Bus ............................... yes
  Qt D-Bus directly linked to libdbus .... no
  Qt Gui ................................. yes
  Qt Network ............................. yes
  Qt Sql ................................. yes
  Qt Testlib ............................. yes
  Qt Widgets ............................. yes
  Qt Xml ................................. yes
Support enabled for:
  Using pkg-config ....................... yes
  QML debugging .......................... yes
  udev ................................... yes
  Using system zlib ...................... yes
Qt Core:
  DoubleConversion ....................... yes
    Using system DoubleConversion ........ no
  GLib ................................... no
  iconv .................................. yes
  ICU .................................... no
  Logging backends:
    journald ............................. no
    syslog ............................... no
    slog2 ................................ no
  Using system PCRE2 ..................... no
Qt Network:
  getaddrinfo() .......................... yes
  getifaddrs() ........................... yes
  IPv6 ifname ............................ yes
  libproxy ............................... no
  OpenSSL ................................ no
    Qt directly linked to OpenSSL ........ no
  SCTP ................................... no
  Use system proxies ..................... yes
Qt Gui:
  Accessibility .......................... yes
  FreeType ............................... yes
    Using system FreeType ................ yes
  HarfBuzz ............................... yes
    Using system HarfBuzz ................ no
  Fontconfig ............................. yes
  Image formats:
    GIF .................................. yes
    ICO .................................. yes
    JPEG ................................. yes
      Using system libjpeg ............... no
    PNG .................................. yes
      Using system libpng ................ no
  EGL .................................... yes
  OpenVG ................................. no
  OpenGL:
    Desktop OpenGL ....................... no
    OpenGL ES 2.0 ........................ yes
    OpenGL ES 3.0 ........................ yes
    OpenGL ES 3.1 ........................ yes
  Session Management ..................... yes
Features used by QPA backends:
  evdev .................................. yes
  libinput ............................... no
  INTEGRITY HID .......................... no
  mtdev .................................. no
  tslib .................................. no
  xkbcommon-evdev ........................ no
QPA backends:
  DirectFB ............................... no
  EGLFS .................................. yes
  EGLFS details:
    EGLFS i.Mx6 .......................... no
    EGLFS i.Mx6 Wayland .................. no
    EGLFS EGLDevice ...................... no
    EGLFS GBM ............................ no
    EGLFS Mali ........................... no
    EGLFS Raspberry Pi ................... no
    EGL on X11 ........................... no
  LinuxFB ................................ yes
  VNC .................................... yes
  Mir client ............................. no
Qt Widgets:
  GTK+ ................................... no
  Styles ................................. Fusion Windows
Qt PrintSupport:
  CUPS ................................... no
Qt Sql:
  DB2 (IBM) .............................. no
  InterBase .............................. no
  MySql .................................. no
  OCI (Oracle) ........................... no
  ODBC ................................... no
  PostgreSQL ............................. no
  SQLite2 ................................ no
  SQLite ................................. yes
    Using system provided SQLite ......... no
  TDS (Sybase) ........................... no
QtXmlPatterns:
  XML schema support ..................... yes
Qt QML:
  QML interpreter ........................ yes
  QML network support .................... yes
Qt Quick:
  Direct3D 12 ............................ no
  AnimatedImage item ..................... yes
  Canvas item ............................ yes
  Support for Qt Quick Designer .......... yes
  Flipable item .......................... yes
  GridView item .......................... yes
  ListView item .......................... yes
  Path support ........................... yes
  PathView item .......................... yes
  Positioner items ....................... yes
  ShaderEffect item ...................... yes
  Sprite item ............................ yes
Qt Gamepad:
  SDL2 ................................... no
Qt Bluetooth:
  BlueZ .................................. no
  BlueZ Low Energy ....................... no
  Linux Crypto API ....................... no
Qt Sensors:
  sensorfw ............................... no
Qt Multimedia:
  ALSA ................................... yes
  GStreamer 1.0 .......................... no
  GStreamer 0.10 ......................... no
  Video for Linux ........................ yes
  OpenAL ................................. no
  PulseAudio ............................. no
  Resource Policy (libresourceqt5) ....... no
  Windows Audio Services ................. no
  DirectShow ............................. no
  Windows Media Foundation ............... no
Qt Quick Controls 2:
  Styles ................................. Default Material Universal
Qt Quick Templates 2:
  Hover support .......................... yes
  Multi-touch support .................... yes
Qt Location:
  Gypsy GPS Daemon ....................... no
  WinRT Geolocation API .................. no
Qt WebEngine:
  Embedded build ......................... yes
  Pepper Plugins ......................... no
  Printing and PDF ....................... no
  Proprietary Codecs ..................... yes
  Spellchecker ........................... yes
  WebRTC ................................. no
  Using system ninja ..................... no
  ALSA ................................... yes
  PulseAudio ............................. no
  System libraries:
    ICU .................................. no
    libwebp and libwebpdemux ............. no
    Opus ................................. no
    ffmpeg ............................... no

Note: Also available for Linux: linux-clang linux-icc

This is the error i am getting.
Now my question is, is it absolutely necessary to use opus and silk for QtWebengine ? If not, how can i avoid it ?
Also why the build is trying to force -mfloat-abi=softfp and -mfpu=neon ?
I did try a build with -mfpu=neon and it is giving me undefined reference to many variiables.

Thank you for your time.

Edit
I tried passing -no-opus to the configuration and still got the same error.

[jsulm]

@name_qt The error message suggests a solution: -mfloat-abi=softfp -mfpu=neon

/opt/arm400-linux/lib/gcc/arm400-linux-gnueabi/4.8.3/include/arm_neon.h:32:2: error: #error You must enable NEON instructions (e.g. -mfloat-abi=softfp -mfpu=neon) to use arm_neon.h

Try to add -mfpu=neon

[Kart]

@jsulm I have tried that too.

I did try a build with -mfpu=neon and it is giving me undefined reference to many variiables.

[Kart]

Does anyone have any suggestions ? I am stuck with this for the last couple of days.

I cross compiled opus separately and linked it with the Qt build. Now the error is something like this.

/opt/arm400-linux/bin/../lib/gcc/arm400-linux-gnueabi/4.8.3/../../../../arm400-linux-gnueabi/bin/ld: error: /opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/qtwebengine/src/core/Release/obj/third_party/WebKit/Source/core/libcore_generated.a(CSSOMKeywords.o) uses VFP register arguments, libQt5WebEngineCore.so.5.9.1 does not
/opt/arm400-linux/bin/../lib/gcc/arm400-linux-gnueabi/4.8.3/../../../../arm400-linux-gnueabi/bin/ld: failed to merge target specific data of file /opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/qtwebengine/src/core/Release/obj/third_party/WebKit/Source/core/libcore_generated.a(CSSOMKeywords.o)
/opt/arm400-linux/bin/../lib/gcc/arm400-linux-gnueabi/4.8.3/../../../../arm400-linux-gnueabi/bin/ld: error: /opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/qtwebengine/src/core/Release/obj/third_party/WebKit/Source/bindings/core/v8/libbindings_core_impl.a(V8StyleMedia.o) uses VFP register arguments, libQt5WebEngineCore.so.5.9.1 does not
/opt/arm400-linux/bin/../lib/gcc/arm400-linux-gnueabi/4.8.3/../../../../arm400-linux-gnueabi/bin/ld: failed to merge target specific data of file /opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/qtwebengine/src/core/Release/obj/third_party/WebKit/Source/bindings/core/v8/libbindings_core_impl.a(V8StyleMedia.o)
/opt/arm400-linux/bin/../lib/gcc/arm400-linux-gnueabi/4.8.3/../../../../arm400-linux-gnueabi/bin/ld: error: /opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/qtwebengine/src/core/Release/obj/third_party/WebKit/Source/core/css/libcss_1.a(CSSRuleList.o) uses VFP register arguments, libQt5WebEngineCore.so.5.9.1 does not
/opt/arm400-linux/bin/../lib/gcc/arm400-linux-gnueabi/4.8.3/../../../../arm400-linux-gnueabi/bin/ld: failed to merge target specific data of file /opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/qtwebengine/src/core/Release/obj/third_party/WebKit/Source/core/css/libcss_1.a(CSSRuleList.o)
/opt/arm400-linux/bin/../lib/gcc/arm400-linux-gnueabi/4.8.3/../../../../arm400-linux-gnueabi/bin/ld: error: /opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/qtwebengine/src/core/Release/obj/third_party/WebKit/Source/core/css/libcss_2.a(MediaValuesInitialViewport.o) uses VFP register arguments, libQt5WebEngineCore.so.5.9.1 does not
/opt/arm400-linux/bin/../lib/gcc/arm400-linux-gnueabi/4.8.3/../../../../arm400-linux-gnueabi/bin/ld: failed to merge target specific data of file /opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/qtwebengine/src/core/Release/obj/third_party/WebKit/Source/core/css/libcss_2.a(MediaValuesInitialViewport.o)
/opt/arm400-linux/bin/../lib/gcc/arm400-linux-gnueabi/4.8.3/../../../../arm400-linux-gnueabi/bin/ld: error: /opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/qtwebengine/src/core/Release/obj/third_party/WebKit/Source/core/layout/svg/libsvg.a(LayoutSVGTSpan.o) uses VFP register arguments, libQt5WebEngineCore.so.5.9.1 does not
/opt/arm400-linux/bin/../lib/gcc/arm400-linux-gnueabi/4.8.3/../../../../arm400-linux-gnueabi/bin/ld: failed to merge target specific data of file /opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/qtwebengine/src/core/Release/obj/third_party/WebKit/Source/core/layout/svg/libsvg.a(LayoutSVGTSpan.o)
/opt/arm400-linux/bin/../lib/gcc/arm400-linux-gnueabi/4.8.3/../../../../arm400-linux-gnueabi/bin/ld: error: /opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/qtwebengine/src/core/Release/obj/ui/gl/libgl_wrapper.a(gl_image_egl.o) uses VFP register arguments, libQt5WebEngineCore.so.5.9.1 does not
/opt/arm400-linux/bin/../lib/gcc/arm400-linux-gnueabi/4.8.3/../../../../arm400-linux-gnueabi/bin/ld: failed to merge target specific data of file /opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/qtwebengine/src/core/Release/obj/ui/gl/libgl_wrapper.a(gl_image_egl.o)
collect2: error: ld returned 1 exit status
Makefile.core_module:81: recipe for target '../../lib/libQt5WebEngineCore.so.5.9.1' failed
make[4]: *** [../../lib/libQt5WebEngineCore.so.5.9.1] Error 1
make[4]: Leaving directory '/opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/qtwebengine/src/core'
Makefile:122: recipe for target 'sub-core_module-pro-make_first' failed
make[3]: *** [sub-core_module-pro-make_first] Error 2
make[3]: Leaving directory '/opt/qt/qt5.9.1arm_source/qt-everywhere-opensource-src-5.9.1/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-5.9.1/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-5.9.1/qtwebengine'
Makefile:834: recipe for target 'module-qtwebengine-make_first' failed
make: *** [module-qtwebengine-make_first] Error 2

[SGaist]

Hi,

From the error message, one is built for soft-float and the other for hard-float. You should check the compilation flags that were used.

[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.