QT WebAssembly

• QT 关于组件管理 问题 ==>要继续此操作，至少需要一个有效且已启用的储存库
• 使用QT WebAssembly将qt程序编译成浏览器可运行的程序。
• 因为Qt特定的sdk对某些版本的emsdk支持比较好，所以得安装相对应的emsdk。
• QT WebAssembly并非支持所有的QT模块。

1. 安装QT 5.13.0支持的emsdk

   安装 1.38.30-64bit
   emsdk install sdk-fastcomp-1.38.30-64bit
   激活
   emsdk activate --embedded  sdk-fastcomp-1.38.30-64bit
   设置环境变量
   emsdk_env.bat

    

2. 安装好mingw32并添加到环境变量中。这里我本机原来交叉编译过vlc代码所以安装过了。具体应该是安装的msys64的安装包
3. 配置sed工具到环境变量中。
4. 进到qt源码目录下，执行指令configure。 这里默认设置了"-static" 和 "-no-feature-thread" 选项，可以通过设置 "-compile-examples" 选项来启用。.这一步花了些时间。如果是动态库和支持多线程，则传递 -shared和-feature-thread 参数。

   configure -no-warnings-are-errors -xplatform wasm-emscripten -platform win32-g++ -nomake examples -prefix %CD%\qtbase

   中间会有编译选择，c 是商业版本，o是开源版本。 y 遵循GNU开源协议等等。

5. mingw32-make启动编译，编译过程中出现错误，查看config.log发现

   > makefile:156: recipe for target 'apphtml' failed
   > mingw32-make: *** [apphtml] Error -1073741515

    

6. 这里看config.log没思路，转而下载了5.14的版本，对应em++改为了支持单线程的1.30.27版本，再次进行configure，时间比较久。

   ====上面有一堆编译cpp的输出，就不贴出来了。
   g++ -o "../bin/qmake.exe" main.o meta.o option.o project.o property.o ioutils.o proitems.o qmakebuiltins.o qmakeevaluator.o qmakeglobals.o qmakeparser.o qmakevfs.o pbuilder_pbx.o makefile.o makefiledeps.o metamakefile.o projectgenerator.o unixmake2.o unixmake.o mingw_make.o msbuild_objectmodel.o msvc_nmake.o msvc_objectmodel.o msvc_vcproj.o msvc_vcxproj.o winmakefile.o xmloutput.o qutfcodec.o qendian.o qglobal.o qlogging.o qmalloc.o qnumeric.o qoperatingsystemversion.o qrandom.o qabstractfileengine.o qbuffer.o qdatastream.o qdebug.o qdir.o qdiriterator.o qfile.o qfiledevice.o qfileinfo.o qfilesystemengine.o qfilesystementry.o qfsfileengine.o qfsfileengine_iterator.o qiodevice.o qsettings.o qtemporaryfile.o qtextstream.o qjsonarray.o qjson.o qjsondocument.o qjsonobject.o qjsonparser.o qjsonvalue.o qmetatype.o qsystemerror.o qvariant.o quuid.o qarraydata.o qbitarray.o qbytearray.o qbytearraylist.o qbytearraymatcher.o qcalendar.o qgregoriancalendar.o qromancalendar.o qcryptographichash.o qdatetime.o qhash.o qlist.o qlocale.o qlocale_tools.o qmap.o qregexp.o qringbuffer.o qstringbuilder.o qstring.o qstringlist.o qversionnumber.o qvsnprintf.o qxmlstream.o qxmlutils.o qfilesystemengine_win.o qfilesystemiterator_win.o qfsfileengine_win.o qlocale_win.o qsettings_win.o qoperatingsystemversion_win.o qsystemlibrary.o registry.o  qlibraryinfo.o -static -s -lole32 -luuid -ladvapi32 -lkernel32 -lnetapi32 -Wl,--gc-sections
   Info: creating super cache file G:\Qt\Qt5.14.2_new\5.14.2\Src\.qmake.super
   Info: creating cache file G:\Qt\Qt5.14.2_new\5.14.2\Src\.qmake.cache
   Info: creating stash file G:\Qt\Qt5.14.2_new\5.14.2\Src\.qmake.stash
   
   Selecting Qt Edition.
   
   Type 'c' if you want to use the Commercial Edition.
   Type 'o' if you want to use the Open Source Edition.
   
   Which edition of Qt do you want to use? o
   
   This is the Qt Open Source Edition.
   
   You are licensed to use this software under the terms of
   the GNU General Public License (GPL) version 3.
   
   Type 'G' to view the GNU General Public License version 3 (GPLv3).
   Type 'y' to accept this license offer.
   Type 'n' to decline this license offer.
   
   Do you accept the terms of the license? y
   
   
   Running configuration tests...
   Checking for valid makespec... yes
   Checking for target architecture... wasm
   Checking for host architecture... i386
   Checking for alloca() in alloca.h... yes
   Checking for C++14 support... no
   Checking for C99 support... yes
   Checking for C11 support... yes
   Checking for pkg-config... no
   Checking for dlopen()... yes
   Checking for support for split sections and linker garbage collection... no
   Checking for D-Bus >= 1.2 (host)... yes
   Checking for IncrediBuild... yes
   Checking for udev... no
   Checking for POSIX fallocate()... yes
   Checking for precompiled header support... no
   Checking for RDRAND instruction... no
   Checking for symbol visibility support... yes
   Checking for -Bsymbolic-functions support... no
   Checking for Signaling NaN for doubles... yes
   Checking for STL compatibility... yes
   Checking for zlib... no
   Checking for Zstandard... no
   Checking for clock_gettime()... yes
   Checking for POSIX monotonic clock... yes
   Checking for C++11 ... yes
   Checking for futimens()... yes
   Checking for getentropy()... no
   Checking for GLib... no
   Checking for POSIX iconv... yes
   Checking for ICU... no
   Checking for inotify... no
   Checking for SysV IPC... no
   Checking for POSIX IPC... no
   Checking for pollts()... no
   Checking for poll()... yes
   Checking for PCRE2... no
   Checking for slog2... no
   Checking for 64 bit atomics... yes
   Checking for DoubleConversion... no
   Checking for O_CLOEXEC... no
   Checking for C++11 ... yes
   Checking for working std::atomic for function pointers... yes
   Checking for getifaddrs()... no
   Checking for KRB5 GSSAPI Support... no
   Checking for IPv6 ifname... no
   Checking for OpenGL ES 2.0... yes
   Checking for KMS... no
   Checking for EGL... yes
   Checking for FreeType... no
   Checking for GBM... no
   Checking for LinuxFB... no
   Checking for mtdev... no
   Checking for OpenGL ES 3.0... no
   Checking for OpenVG... no
   Checking for default QPA platform... wasm
   Checking for HarfBuzz... no
   Checking for libjpeg... no
   Checking for libmd4c... no
   Checking for tslib... no
   Checking for Vulkan... no
   Checking for XLib... no
   Checking for xkbcommon >= 0.5.0... no
   Checking for CUPS... no
   Checking for DB2 (IBM)... no
   Checking for InterBase... no
   Checking for MySQL... no
   Checking for OCI (Oracle)... no
   Checking for ODBC... no
   Checking for PostgreSQL... no
   Checking for SQLite (version 2)... no
   Checking for TDS (Sybase)... no
   Checking for C++14 make_unique()... no
   Checking for Direct3D 12... no
   Checking for Assimp... no
   Checking for SDL2... no
   Checking for Autodesk FBX... no
   Checking for Wayland client library... no
   Checking for Wayland EGL library... no
   Checking for wayland-server... no
   Checking for BlueZ... no
   Checking for sensorfw... no
   Checking for Gypsy... no
   Checking for WinRT Geolocation API... no
   Checking for ALSA... no
   Checking for Vivante GPU... no
   Checking for GStreamer 1.0... no
   Checking for GStreamer 0.10... no
   Checking for Video for Linux... no
   Checking for OpenAL... yes
   Checking for PulseAudio >= 0.9.10... no
   Checking for libresourceqt5... no
   Checking for Flite... no
   Checking for Speech Dispatcher... no
   Checking for libclang... 系统找不到指定的路径。
   no
   Checking for architecture supported... no
   Checking for bison... yes
   Checking for python2... G:/Work/WebAssembly/emsdk_1.38.27/python/2.7.13.1_64bit/python-2.7.13.amd64/python.exe
   Checking for gperf... yes
   Checking for flex... yes
   Checking for submodule initialized... yes
   Checking for build path without whitespace... yes
   Checking for host pkg-config...
   Checking for jumbo build merge limit... 8
   Checking for platform supported... Unknown platform. Qt WebEngine only supports Linux, Windows, and macOS.
   Checking for d-bus... no
   Checking for fontconfig... no
   Checking for glib-2.0 >= 2.32.0... no
   Checking for jsoncpp... no
   Checking for khr... yes
   Checking for lcms2... no
   Checking for libdrm... no
   Checking for libevent... no
   Checking for libvpx... no
   Checking for libwebp, libwebpmux and libwebpdemux... no
   Checking for compatible libxml2 and libxslt... no
   Checking for minizip... no
   Checking for system ninja... yes
   Checking for nss >= 3.26... no
   Checking for opus... no
   Checking for protobuf... no
   Checking for re2... no
   Checking for snappy... no
   Checking for x11... no
   Checking for xcomposite... no
   Checking for xcursor... no
   Checking for xi... no
   Checking for xtst... no
   Done running configuration tests.
   
   Configure summary:
   
   Building on: win32-g++ (i386, CPU features: )
   Building for: wasm-emscripten (wasm, CPU features: )
   Target compiler: clang 6.0.1
   Configuration: cross_compile largefile release c++11 no-pkg-config reduce_exports static stl
   Build options:
     Mode ................................... release
     Optimize release build for size ........ no
     Building shared libraries .............. no
     Using C standard ....................... C11
     Using C++ standard ..................... C++11
     Using ccache ........................... no
     Relocatable ............................ no
     Using precompiled headers .............. no
     Using LTCG ............................. no
     Target compiler supports:
     Build parts ............................ libs
   Qt modules and options:
     Qt Concurrent .......................... no
     Qt D-Bus ............................... no
     Qt D-Bus directly linked to libdbus .... no
     Qt Gui ................................. yes
     Qt Network ............................. yes
     Qt Sql ................................. no
     Qt Testlib ............................. yes
     Qt Widgets ............................. yes
     Qt Xml ................................. yes
   Support enabled for:
     Using pkg-config ....................... no
     udev ................................... no
     Using system zlib ...................... no
     Zstandard support ...................... no
   Qt Core:
     DoubleConversion ....................... yes
       Using system DoubleConversion ........ no
     GLib ................................... no
     iconv .................................. yes
     ICU .................................... no
     Built-in copy of the MIME database ..... yes
     Tracing backend ........................ 
     Logging backends:
       journald ............................. no
       syslog ............................... no
       slog2 ................................ no
     PCRE2 .................................. yes
       Using system PCRE2 ................... no
   Qt Network:
     getifaddrs() ........................... no
     IPv6 ifname ............................ no
     libproxy ............................... no
     OpenSSL ................................ no
       Qt directly linked to OpenSSL ........ no
     OpenSSL 1.1 ............................ no
     DTLS ................................... no
     OCSP-stapling .......................... no
     SCTP ................................... no
     Use system proxies ..................... yes
     GSSAPI ................................. no
   Qt Gui:
     Accessibility .......................... yes
     FreeType ............................... yes
       Using system FreeType ................ no
     HarfBuzz ............................... yes
       Using system HarfBuzz ................ no
     Fontconfig ............................. no
     Image formats:
       GIF .................................. yes
       ICO .................................. yes
       JPEG ................................. yes
         Using system libjpeg ............... no
       PNG .................................. yes
         Using system libpng ................ no
     Text formats:
       HtmlParser ........................... yes
       CssParser ............................ yes
       OdfWriter ............................ yes
       MarkdownReader ....................... yes
         Using system libmd4c ............... no
       MarkdownWriter ....................... yes
     EGL .................................... yes
     OpenVG ................................. no
     OpenGL:
       Desktop OpenGL ....................... no
       OpenGL ES 2.0 ........................ yes
       OpenGL ES 3.0 ........................ no
       OpenGL ES 3.1 ........................ no
       OpenGL ES 3.2 ........................ no
     Vulkan ................................. no
     Session Management ..................... yes
   Features used by QPA backends:
     evdev .................................. no
     libinput ............................... no
     INTEGRITY HID .......................... no
     mtdev .................................. no
     tslib .................................. no
     xkbcommon .............................. no
     X11 specific:
       XLib ................................. no
       XCB Xlib ............................. no
       EGL on X11 ........................... no
   QPA backends:
     DirectFB ............................... no
     EGLFS .................................. no
     LinuxFB ................................ no
     VNC .................................... yes
   Qt Sql:
     SQL item models ........................ yes
   Qt Widgets:
     GTK+ ................................... no
     Styles ................................. Fusion Windows
   Qt PrintSupport:
     CUPS ................................... no
   Qt Sql Drivers:
     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
   Qt Testlib:
     Tester for item models ................. yes
   Qt SerialBus:
     Socket CAN ............................. no
     Socket CAN FD .......................... no
     SerialPort Support ..................... no
   Further Image Formats:
     JasPer ................................. no
     MNG .................................... no
     TIFF ................................... yes
       Using system libtiff ................. no
     WEBP ................................... yes
       Using system libwebp ................. no
   Qt QML:
     QML network support .................... yes
     QML debugging and profiling support .... yes
     QML just-in-time compiler .............. no
     QML sequence object .................... yes
     QML XML http request ................... yes
     QML Locale ............................. yes
   Qt QML Models:
     QML list model ......................... yes
     QML delegate model ..................... 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
     TableView item ......................... yes
     Path support ........................... yes
     PathView item .......................... yes
     Positioner items ....................... yes
     Repeater item .......................... yes
     ShaderEffect item ...................... yes
     Sprite item ............................ yes
   QtQuick3D:
     Assimp ................................. yes
     System Assimp .......................... no
   Qt Scxml:
     ECMAScript data model for QtScxml ...... yes
   Qt Gamepad:
     SDL2 ................................... no
   Qt 3D GeometryLoaders:
     Autodesk FBX ........................... no
   Qt Wayland Client ........................ no
   Qt Wayland Compositor .................... no
   Qt Bluetooth:
     BlueZ .................................. no
     BlueZ Low Energy ....................... no
     Linux Crypto API ....................... no
     Native Win32 Bluetooth ................. no
     WinRT Bluetooth API (desktop & UWP) .... no
     WinRT advanced bluetooth low energy API (desktop & UWP) . no
   Qt Sensors:
     sensorfw ............................... no
   Qt Quick Controls 2:
     Styles ................................. Default Fusion Imagine Material Universal
   Qt Quick Templates 2:
     Hover support .......................... yes
     Multi-touch support .................... yes
   Qt Positioning:
     Gypsy GPS Daemon ....................... no
     WinRT Geolocation API .................. no
   Qt Location:
     Qt.labs.location experimental QML plugin . yes
     Geoservice plugins:
       OpenStreetMap ........................ no
       HERE ................................. yes
       Esri ................................. yes
       Mapbox ............................... yes
       MapboxGL ............................. no
       Itemsoverlay ......................... yes
   QtXmlPatterns:
     XML schema support ..................... yes
   Qt Multimedia:
     ALSA ................................... no
     GStreamer 1.0 .......................... no
     GStreamer 0.10 ......................... no
     Video for Linux ........................ no
     OpenAL ................................. yes
     PulseAudio ............................. no
     Resource Policy (libresourceqt5) ....... no
     Windows Audio Services ................. no
     DirectShow ............................. no
     Windows Media Foundation ............... no
   Qt TextToSpeech:
     Flite .................................. no
     Flite with ALSA ........................ no
     Speech Dispatcher ...................... no
   Qt Tools:
     QDoc ................................... no
   Qt WebEngine Build Tools:
     Use System Ninja ....................... yes
     Use System Gn .......................... no
     Jumbo Build Merge Limit ................ 8
     Developer build ........................ no
     QtWebEngine required system libraries:
       fontconfig ........................... no
       dbus ................................. no
       nss .................................. no
       khr .................................. yes
       glibc ................................ no
     Optional system libraries used:
       re2 .................................. no
       icu .................................. no
       libwebp, libwebpmux and libwebpdemux . no
       opus ................................. no
       ffmpeg ............................... no
       libvpx ............................... no
       snappy ............................... no
       glib ................................. no
       zlib ................................. no
       minizip .............................. no
       libevent ............................. no
       jsoncpp .............................. no
       protobuf ............................. no
       libxml2 and libxslt .................. no
       lcms2 ................................ no
       png .................................. no
       JPEG ................................. no
       harfbuzz ............................. no
       freetype ............................. no
   
   Note: Using static linking will disable the use of dynamically
   loaded plugins. Make sure to import all needed static plugins,
   or compile needed modules into the library.
   
   Note: No wayland-egl support detected. Cross-toolkit compatibility disabled.
   
   Note: The following modules are not being compiled in this configuration:
       serialport
       3dcore
       3drender
       webenginecore
       webengine
       webenginewidgets
   
   WARNING: QDoc will not be compiled, probably because libclang could not be located. This means that you cannot build the Qt documentation.
   
   Either ensure that llvm-config is in your PATH environment variable, or set LLVM_INSTALL_DIR to the location of your llvm installation.
   On Linux systems, you may be able to install libclang by installing the libclang-dev or libclang-devel package, depending on your distribution.
   On macOS, you can use Homebrew's llvm package.
   On Windows, you must set LLVM_INSTALL_DIR to the installation path.
   
   WARNING: Unknown platform. Qt WebEngine only supports Linux, Windows, and macOS.
   
   WARNING: QtWebEngine will not be built.
   
   WARNING: QtPdf will not be built.
   
   Qt is now configured for building. Just run 'mingw32-make'.
   Once everything is built, Qt is installed.
   You should NOT run 'mingw32-make install'.
   Note that this build cannot be deployed to other machines or devices.
   
   Prior to reconfiguration, make sure you remove any leftovers from
   the previous build.

    

7. 这里说需要配置llvm-config路径，暂时没配置。按照官方教程直接make，发现make不识别。所以根据上述提示，执行mingw32-make，发现ok

   mingw32-make module-qtbase

   这一步要等比较长时间。

8. 编译报错了！

   In file included from G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/include/QtCore/qglobal.h:1:0,
                    from G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/include/QtCore/../../src/corelib/text/qchar.h:43,
                    from G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/include/QtCore/qchar.h:1,
                    from G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/include/QtCore/../../src/corelib/text/qstring.h:49,
                    from G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/include/QtCore/qstring.h:1,
                    from G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/include/QtCore/../../src/corelib/io/qdir.h:43,
                    from G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/include/QtCore/qdir.h:1,
                    from G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/src/corelib/global/qlibraryinfo.cpp:41:
   G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/include/QtCore/../../src/corelib/global/qglobal.h:86:30: error: division by zero in #if
    #define QT_CONFIG(feature) (1/QT_FEATURE_##feature == 1)
                                 ^
   G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/src/corelib/global/qlibraryinfo.cpp:676:7: note: in expansion of macro 'QT_CONFIG'
    #elif QT_CONFIG(relocatable)
          ^
   makefile:336: recipe for target 'qlibraryinfo_final.o' failed
   mingw32-make[3]: *** [qlibraryinfo_final.o] Error 1
   mingw32-make[3]: Leaving directory 'G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/qmake'
   Makefile.qmake-aux:261: recipe for target 'G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/qmake/qmake.exe' failed
   mingw32-make[2]: *** [G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/qmake/qmake.exe] Error 2
   mingw32-make[2]: Leaving directory 'G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase/qmake'
   Makefile:125: recipe for target 'sub-qmake-qmake-aux-pro-make_first' failed
   mingw32-make[1]: *** [sub-qmake-qmake-aux-pro-make_first] Error 2
   mingw32-make[1]: Leaving directory 'G:/Qt/Qt5.14.2_new/5.14.2/Src/qtbase'
   makefile:84: recipe for target 'module-qtbase' failed
   mingw32-make: *** [module-qtbase] Error 2

   从错误地方看，是因为QT_CONFIG(relocatable)这个宏执行时候，QT_FEATURE##feature为0了，进到qglobal.h中看到有这么一句注释

   /*
       The QT_CONFIG macro implements a safe compile time check for features of Qt.
       Features can be in three states:
           0 or undefined: This will lead to a compile error when testing for it
           -1: The feature is not available
           1: The feature is available
   */

   看来是没定义，那么我们在qlibraryinfo.cpp中，加上这个宏定义是不是就可以了？试一下，qlibraryinfo.cpp中添加#include “qconfig_p.h”然后继续执行 mingw32-make，稍等片刻，很顺利，编译过了。

9. 编译demo

   1. 执行qtbase下面的qmake qtbase\bin\qmake E:\GitPro\qt-webassembly-examples\widgets_wiggly\widgets_wiggly.pro

   2. 执行  mingw32-make

   3. 最后发现文件生成在了G:\Qt\Qt5.14.2\5.14.2\Src目录下：

      1. widgets_wiggly.js 

      2. widgets_wiggly.wasm 

      3. widgets_wiggly.html

10. 在src目录下启动http服务器 python -m http.server(python3版本, 2.7是python -m SimpleHTTPServer 8000)。打开http://localhost:8000/widgets_wiggly.html 即可看到了。
11. 多线程目前只支持std::thread 不支持QThread。
12. firefox 多线程设置：about:config 并设置javascript.options.wasm 为true
13. chrome 多线程设置：chrome://flags/ 搜索webassembly
14. 由于qt编译的是静态库，所以测试加载静态库。
    1. 编译静态库，注意最后生成的xxx.a文件。
    2. 编译使用静态库的程序，工程上右键添加库--》外部库--》勾选windows和linux，静态库，去掉加d的选项
    3. 
    4. 这个包含路径是包含库头文件的路径，自行修改即可。
    5. 设置完后 qmake xxx.pro --> mingw32-make

15. qt WebAssembly对汇编的支持情况

    1. asm("hlt");==》让cpu暂停下，编译报错，后续研究。
    2. 错误截图

16. 参考文章
    

      https://www.jianshu.com/p/3ef1dfabab68

      https://forum.qt.io/topic/107137/qt-for-webassembly-on-windows-10/2