libreoffice-online/wasm
Michael Stahl b1a1522a2b WASM use same CXXFLAGS as core
-pthreads is required, or wasm-ld reports errors about
"was not compiled with 'atomics' or 'bulk-memory' features"

Also, POCO needs to be built with this, add it in README.

Signed-off-by: Michael Stahl <michael.stahl@allotropia.de>
Change-Id: Ie83e3942e5fc689e6df5a5a705d7ee2e1325ce03
2023-01-10 22:02:22 +02:00
..
Makefile.am WASM use same CXXFLAGS as core 2023-01-10 22:02:22 +02:00
poco-1.12.4-emscripten.patch
poco-devel-emscripten.patch
README WASM use same CXXFLAGS as core 2023-01-10 22:02:22 +02:00
wasmapp.cpp
wasmapp.hpp

= WASM with emscripten =

Building for WASM with emscripten is still a bit immature and many projects
need patching to work.

Note that there are wrapper tools like "emconfigure", "emmake", "emcmake" that
tend to set up environment variables like CC properly, although some project's
build system unfortunately override that.

For convenience it's recommended to build with a docker container that has the
required build tools.

    podman pull public.ecr.aws/allotropia/libo-builders/wasm

== Build dependencies ==

First you need to build LibreOffice core with emscripten.
Currently best to use "feature/wasm" branch.

    podman run -v $HOME/lo/feature_wasm:$HOME/lo/feature_wasm:ro -v /data/lo/build_feature_wasm:/data/lo/build_feature_wasm -v $HOME/lo/ext_sources:/ext_sources:ro --security-opt=label=disable -ti public.ecr.aws/allotropia/libo-builders/wasm /bin/bash -c 'source /home/builder/emsdk/emsdk_env.sh && cd /data/lo/build_feature_wasm/ && /home/ms/lo/feature_wasm/autogen.sh --with-external-tar=/ext_sources --with-distro=LibreOfficeWASM32'

    podman run -v $HOME/lo/feature_wasm:$HOME/lo/feature_wasm:ro -v /data/lo/build_feature_wasm:/data/lo/build_feature_wasm -v $HOME/lo/ext_sources:/ext_sources:rw --security-opt=label=disable -ti public.ecr.aws/allotropia/libo-builders/wasm /bin/bash -c 'source /home/builder/emsdk/emsdk_env.sh && cd /data/lo/build_feature_wasm/ && make -rj8'

Then build libzstd:
* with assembly code disabled
* using the Makefile (didn't try its other build systems)

    tar -xzvf ~/Downloads/zstd-1.5.2.tar.gz
    cd zstd-1.5.2/
    podman run -v /data/lo/zstd-1.5.2:/data/lo/zstd-1.5.2:rw --security-opt=label=disable -ti public.ecr.aws/allotropia/libo-builders/wasm /bin/bash -c 'source /home/builder/emsdk/emsdk_env.sh && cd /data/lo/zstd-1.5.2/ && emmake make -j8 lib-nomt ZSTD_NO_ASM=1'

Then build POCO:
* this requires a patch (currently exists patch for 1.12.4 and untested "devel"
  branch)
* note that the header Poco/Platform.h maps EMSCRIPTEN to POCO_OS_LINUX
* it has both Makefiles and CMake but i couldn't get CMake to use CXXFLAGS to
  disable some Linux-specific code; i tried variations on:
    emcmake cmake -S .. -DENABLE_MONGODB=off -DENABLE_DATA_SQLITE=off -DENABLE_REDIS=off -DENABLE_PROMETHEUS=off -DENABLE_PDF=off -DENABLE_SEVENZIP=off -DENABLE_ZIP=off -DENABLE_CPPPARSER=off -DENABLE_POCODOC=off -DENABLE_PAGECOMPILER=off -DENABLE_PAGECOMPILER_FILE2PAGE=off -DENABLE_ACTIVERECORD=off -DENABLE_ACTIVERECORD_COMPILER=off -DENABLE_DATA=off -DENABLE_DATA_ODBC=off -DENABLE_DATA_POSTGRESQL=off -DENABLE_DATA_MYSQL=off -DENABLE_APACHECONNECTOR=off -DENABLE_JWT=off CXXFLAGS=-DPOCO_NO_LINUX_IF_PACKET_H
* Online requires a single include directory so "make install" must be used

    tar -xjvf ~/Downloads/poco-1.12.4-all.tar.bz2
    cd poco-1.12.4-all
    patch -p1 < $HOME/lo/online/wasm/poco-1.12.4-emscripten.patch
    podman run -v /data/lo/poco-1.12.4-all:/data/lo/poco-1.12.4-all:rw --security-opt=label=disable -ti public.ecr.aws/allotropia/libo-builders/wasm /bin/bash -c 'source /home/builder/emsdk/emsdk_env.sh && cd /data/lo/poco-1.12.4-all && emconfigure ./configure --static --no-samples --no-tests --omit=Crypto,NetSSL_OpenSSL,JWT,Data,Data/SQLite,Data/ODBC,Data/MySQL,Data/PostgreSQL,Zip,PageCompiler,PageCompiler/File2Page,MongoDB,Redis,ActiveRecord,ActiveRecord/Compiler,Prometheus && emmake make -j8 CC=/home/builder/emsdk/upstream/emscripten/emcc CXX=/home/builder/emsdk/upstream/emscripten/em++ LD=/home/builder/emsdk/upstream/emscripten/em++ CXXFLAGS="-DPOCO_NO_LINUX_IF_PACKET_H -pthread -s USE_PTHREADS=1 -s DISABLE_EXCEPTION_CATCHING=0" && make -j8 install INSTALLDIR=/data/lo/poco-1.12.4-all/install'

== Build Online ==

Then build Online itself:

    podman run -v /data/lo/zstd-1.5.2:/data/lo/zstd-1.5.2:ro -v /data/lo/poco-1.12.4-all:/data/lo/poco-1.12.4-all:ro -v $HOME/lo/feature_wasm:$HOME/lo/feature_wasm:ro -v /data/lo/build_feature_wasm:/data/lo/build_feature_wasm:ro -v $HOME/lo/online:$HOME/lo/online:rw -v /data/lo/build_online_wasm:/data/lo/build_online_wasm:rw --security-opt=label=disable -ti public.ecr.aws/allotropia/libo-builders/wasm /bin/bash -c "source /home/builder/emsdk/emsdk_env.sh && cd /data/lo/build_online_wasm/ && /home/ms/lo/online/autogen.sh && emconfigure /home/ms/lo/online/configure --with-lokit-path=$HOME/lo/feature_wasm/include --with-lo-path=/data/lo/build_feature_wasm/instdir --with-lo-builddir=/data/lo/build_feature_wasm --with-zstd-includes=/data/lo/zstd-1.5.2/lib --with-zstd-libs=/data/lo/zstd-1.5.2/lib --with-poco-includes=/data/lo/poco-1.12.4-all/install/include --with-poco-libs=/data/lo/poco-1.12.4-all/install/lib --host=wasm32-local-emscripten"
    podman run -v /data/lo/zstd-1.5.2:/data/lo/zstd-1.5.2:ro -v /data/lo/poco-1.12.4-all:/data/lo/poco-1.12.4-all:ro -v $HOME/lo/feature_wasm:$HOME/lo/feature_wasm:ro -v /data/lo/build_feature_wasm:/data/lo/build_feature_wasm:ro -v $HOME/lo/online:$HOME/lo/online:rw -v /data/lo/build_online_wasm:/data/lo/build_online_wasm:rw --security-opt=label=disable -ti public.ecr.aws/allotropia/libo-builders/wasm /bin/bash -c "source /home/builder/emsdk/emsdk_env.sh && cd /data/lo/build_online_wasm/ && emmake make"