opencv_js.worker.js with MODULARIZE generates invalid code

[simonbuehler]

hi,

when trying to run opencv.js wasm + simd (works) + threads (there it explodes) with this command:

/home/user/opencv/emsdk/upstream/emscripten/em++ -s WASM=1 -s SINGLE_FILE=1 -s USE_PTHREADS=1 -s PTHREAD_POOL_SIZE=8 -msimd128  -s ENVIRONMENT=web,worker    -fsigned-char -W -Wall -Wreturn-type -Wnon-virtual-dtor -Waddress -Wsequence-point -Wformat -Wformat-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winconsistent-missing-override -Wno-delete-non-virtual-dtor -Wno-unnamed-type-template-args -Wno-comment -Wno-deprecated-enum-enum-conversion -Wno-deprecated-anon-enum-enum-conversion -fdiagnostics-show-option -pthread -Qunused-arguments -ffunction-sections -fdata-sections  -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG  -DNDEBUG   -Wl,--gc-sections  --memory-init-file 0 -s TOTAL_MEMORY=128MB -s WASM_MEM_MAX=4GB -s ALLOW_MEMORY_GROWTH=1 -s MODULARIZE=1 -s EXPORT_NAME="'cv'" -s DEMANGLE_SUPPORT=1 -s FORCE_FILESYSTEM=1 --use-preload-plugins --bind --post-js /home/user/opencv/emsdk/opencv/modules/js/src/helpers.js  -Wno-missing-prototypes @CMakeFiles/opencv_js.dir/objects1.rsp -o ../../bin/opencv_js.js @CMakeFiles/opencv_js.dir/linklibs.rsp

the generated worker code contains this part:

  Module["wasmMemory"] = e.data.wasmMemory;
      Module["buffer"] = Module["wasmMemory"].buffer;
      Module["ENVIRONMENT_IS_PTHREAD"] = true;
      if (typeof e.data.urlOrBlob == "string") {
        importScripts(e.data.urlOrBlob);
      } else {
        var objectUrl = URL.createObjectURL(e.data.urlOrBlob);
        importScripts(objectUrl);
        URL.revokeObjectURL(objectUrl);
      }
      //cv(Module); <-- cv is not defined here
    } else if (e.data.cmd === "run") {
      Module["__emscripten_thread_init"](e.data.pthread_ptr, 0, 0, 1);
      Module["__emscripten_thread_mailbox_await"](e.data.pthread_ptr);
      Module["establishStackSpace"]();
      Module["PThread"].receiveObjectTransfer(e.data);

which has the source here:

emscripten/src/worker.js

Line 209 in 58cf85c

{{{ EXPORT_NAME }}}(Module);

i just commented it out, and it works(?)

• Is this valid to just comment out?
• why is cv not defined, is it a async issue?
• whats the idea of a cv(Module) call

[simonbuehler]

Details

user@DESKTOP-68JUJRU:~/opencv/emsdk$ python ./opencv/platforms/js/build_js.py --cmake_option="-DCMAKE_TOOLCHAIN_FILE=/home/user/opencv/emsdk/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake" --cmake_option="-DCMAKE_CROSSCOMPILING_EMULATOR=/home/user/opencv/emsdk/node/16.20.0_64bit/bin/node" build_wasm --build_wasm --simd --threads --build_flags=" -s ENVIRONMENT=web,worker " Args: Namespace(build_dir='build_wasm', opencv_dir='/home/user/opencv/emsdk/opencv', emscripten_dir='/home/user/opencv/emsdk', build_wasm=True, disable_wasm=False, disable_single_file=False, threads=True, simd=True, build_test=False, build_perf=False, build_doc=False, build_loader=False, clean_build_dir=False, skip_config=False, config_only=False, enable_exception=False, cmake_option=['-DCMAKE_TOOLCHAIN_FILE=/home/user/opencv/emsdk/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake', '-DCMAKE_CROSSCOMPILING_EMULATOR=/home/user/opencv/emsdk/node/16.20.0_64bit/bin/node'], build_flags=' -s ENVIRONMENT=web,worker ', build_wasm_intrin_test=False, config='/home/user/opencv/emsdk/opencv/platforms/js/opencv_js.config.py', webnn=False) Check dir /home/user/opencv/emsdk/build_wasm (create: True, clean: False) Check dir /home/user/opencv/emsdk/opencv (create: False, clean: False) ----------------------------------------------------------- options.opencv_dir: /home/user/opencv/emsdk/opencv Check dir /home/user/opencv/emsdk (create: False, clean: False) ===== ===== Config OpenCV.js build for wasm ===== Executing: ['cmake', '-DPYTHON_DEFAULT_EXECUTABLE=/usr/bin/python', '-DENABLE_PIC=FALSE', '-DCMAKE_BUILD_TYPE=Release', "-DCMAKE_TOOLCHAIN_FILE='/home/user/opencv/emsdk/cmake/Modules/Platform/Emscripten.cmake'", "-DCPU_BASELINE=''", '-DCMAKE_INSTALL_PREFIX=/usr/local', "-DCPU_DISPATCH=''", '-DCV_TRACE=OFF', '-DBUILD_SHARED_LIBS=OFF', '-DWITH_1394=OFF', '-DWITH_ADE=OFF', '-DWITH_VTK=OFF', '-DWITH_EIGEN=OFF', '-DWITH_FFMPEG=OFF', '-DWITH_GSTREAMER=OFF', '-DWITH_GTK=OFF', '-DWITH_GTK_2_X=OFF', '-DWITH_IPP=OFF', '-DWITH_JASPER=OFF', '-DWITH_JPEG=OFF', '-DWITH_WEBP=OFF', '-DWITH_OPENEXR=OFF', '-DWITH_OPENGL=OFF', '-DWITH_OPENVX=OFF', '-DWITH_OPENNI=OFF', '-DWITH_OPENNI2=OFF', '-DWITH_PNG=OFF', '-DWITH_TBB=OFF', '-DWITH_TIFF=OFF', '-DWITH_V4L=OFF', '-DWITH_OPENCL=OFF', '-DWITH_OPENCL_SVM=OFF', '-DWITH_OPENCLAMDFFT=OFF', '-DWITH_OPENCLAMDBLAS=OFF', '-DWITH_GPHOTO2=OFF', '-DWITH_LAPACK=OFF', '-DWITH_ITT=OFF', '-DWITH_QUIRC=ON', '-DBUILD_ZLIB=ON', '-DBUILD_opencv_apps=OFF', '-DBUILD_opencv_calib3d=ON', '-DBUILD_opencv_dnn=ON', '-DBUILD_opencv_features2d=ON', '-DBUILD_opencv_flann=ON', '-DBUILD_opencv_gapi=OFF', '-DBUILD_opencv_ml=OFF', '-DBUILD_opencv_photo=ON', '-DBUILD_opencv_imgcodecs=OFF', '-DBUILD_opencv_shape=OFF', '-DBUILD_opencv_videoio=OFF', '-DBUILD_opencv_videostab=OFF', '-DBUILD_opencv_highgui=OFF', '-DBUILD_opencv_superres=OFF', '-DBUILD_opencv_stitching=OFF', '-DBUILD_opencv_java=OFF', '-DBUILD_opencv_js=ON', '-DBUILD_opencv_python2=OFF', '-DBUILD_opencv_python3=OFF', '-DBUILD_EXAMPLES=ON', '-DBUILD_PACKAGE=OFF', '-DBUILD_TESTS=ON', '-DBUILD_PERF_TESTS=ON', '-DCMAKE_TOOLCHAIN_FILE=/home/user/opencv/emsdk/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake', '-DCMAKE_CROSSCOMPILING_EMULATOR=/home/user/opencv/emsdk/node/16.20.0_64bit/bin/node', '-DBUILD_DOCS=OFF', '-DWITH_PTHREADS_PF=ON', '-DCV_ENABLE_INTRINSICS=ON', '-DBUILD_WASM_INTRIN_TESTS=OFF', "-DCMAKE_C_FLAGS='-s WASM=1 -s SINGLE_FILE=1 -s USE_PTHREADS=1 -s PTHREAD_POOL_SIZE=8 -msimd128 -s ENVIRONMENT=web,worker '", "-DCMAKE_CXX_FLAGS='-s WASM=1 -s SINGLE_FILE=1 -s USE_PTHREADS=1 -s PTHREAD_POOL_SIZE=8 -msimd128 -s ENVIRONMENT=web,worker '", '/home/user/opencv/emsdk/opencv'] Re-run cmake no build system arguments -- Detected processor: x86 -- Looking for ccache - not found -- Could NOT find OpenJPEG (minimal suitable version: 2.0, recommended version >= 2.3.1). OpenJPEG will be built from sources -- OpenJPEG: VERSION = 2.5.0, BUILD = opencv-4.8.0-dev-openjp2-2.5.0 -- OpenJPEG libraries will be built from sources: libopenjp2 (version "2.5.0") -- libva: missing va.h header (VA_INCLUDE_DIR) -- Module opencv_ts disabled because opencv_imgcodecs dependency can't be resolved! -- Allocator metrics storage type: 'long long' -- Excluding from source files list: modules/imgproc/src/corner.avx.cpp -- Excluding from source files list: modules/imgproc/src/imgwarp.avx2.cpp -- Excluding from source files list: modules/imgproc/src/imgwarp.lasx.cpp -- Excluding from source files list: modules/imgproc/src/imgwarp.sse4_1.cpp -- Excluding from source files list: modules/imgproc/src/resize.avx2.cpp -- Excluding from source files list: modules/imgproc/src/resize.lasx.cpp -- Excluding from source files list: modules/imgproc/src/resize.sse4_1.cpp -- Registering hook 'INIT_MODULE_SOURCES_opencv_dnn': /home/user/opencv/emsdk/opencv/modules/dnn/cmake/hooks/INIT_MODULE_SOURCES_opencv_dnn.cmake -- opencv_dnn: filter out ocl4dnn source code -- opencv_dnn: filter out cuda4dnn source code -- Excluding from source files list: modules/dnn/src/layers/cpu_kernels/conv_winograd_f63.neon.cpp -- Excluding from source files list: /modules/dnn/layers/layers_common.avx.cpp -- Excluding from source files list: /modules/dnn/layers/layers_common.avx2.cpp -- Excluding from source files list: /modules/dnn/layers/layers_common.avx512_skx.cpp -- Excluding from source files list: /modules/dnn/layers/layers_common.rvv.cpp -- Excluding from source files list: /modules/dnn/layers/layers_common.lasx.cpp -- Excluding from source files list: /modules/dnn/int8layers/layers_common.avx2.cpp -- Excluding from source files list: /modules/dnn/int8layers/layers_common.avx512_skx.cpp -- Excluding from source files list: /modules/dnn/int8layers/layers_common.lasx.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/conv_block.avx.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/conv_block.avx2.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/conv_block.neon.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/conv_block.neon_fp16.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/conv_depthwise.avx.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/conv_depthwise.avx2.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/conv_depthwise.rvv.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/conv_depthwise.lasx.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/conv_winograd_f63.avx.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/conv_winograd_f63.avx2.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/conv_winograd_f63.neon_fp16.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/fast_gemm_kernels.avx.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/fast_gemm_kernels.avx2.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/fast_gemm_kernels.neon.cpp -- Excluding from source files list: /modules/dnn/layers/cpu_kernels/fast_gemm_kernels.lasx.cpp -- Excluding from source files list: modules/features2d/src/fast.avx2.cpp -- Wrapped in JavaScript(js): -- opencv_core -- opencv_imgproc -- opencv_photo -- opencv_dnn -- opencv_features2d -- opencv_calib3d -- opencv_objdetect -- opencv_video -- Found 'misc' Python modules from /home/user/opencv/emsdk/opencv/modules/python/package/extra_modules -- Found 'mat_wrapper;utils' Python modules from /home/user/opencv/emsdk/opencv/modules/core/misc/python/package -- -- General configuration for OpenCV 4.8.0-dev ===================================== -- Version control: 4.8.0-417-g2c1ec4245d-dirty -- -- Platform: -- Timestamp: 2023-11-27T14:22:05Z -- Host: Linux 4.19.128-microsoft-standard x86_64 -- Target: Emscripten 1 x86 -- CMake: 3.22.1 -- CMake generator: Unix Makefiles -- CMake build tool: /usr/bin/gmake -- Configuration: Release -- -- CPU/HW features: -- Baseline: -- -- C/C++: -- Built as dynamic libs?: NO -- C++ standard: 11 -- C++ Compiler: /home/user/opencv/emsdk/upstream/emscripten/em++ (ver 18.0.0) -- C++ flags (Release): -s WASM=1 -s SINGLE_FILE=1 -s USE_PTHREADS=1 -s PTHREAD_POOL_SIZE=8 -msimd128 -s ENVIRONMENT=web,worker -fsigned-char -W -Wall -Wreturn-type -Wnon-virtual-dtor -Waddress -Wsequence-point -Wformat -Wformat-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winconsistent-missing-override -Wno-delete-non-virtual-dtor -Wno-unnamed-type-template-args -Wno-comment -Wno-deprecated-enum-enum-conversion -Wno-deprecated-anon-enum-enum-conversion -fdiagnostics-show-option -pthread -Qunused-arguments -ffunction-sections -fdata-sections -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG -DNDEBUG -- C++ flags (Debug): -s WASM=1 -s SINGLE_FILE=1 -s USE_PTHREADS=1 -s PTHREAD_POOL_SIZE=8 -msimd128 -s ENVIRONMENT=web,worker -fsigned-char -W -Wall -Wreturn-type -Wnon-virtual-dtor -Waddress -Wsequence-point -Wformat -Wformat-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winconsistent-missing-override -Wno-delete-non-virtual-dtor -Wno-unnamed-type-template-args -Wno-comment -Wno-deprecated-enum-enum-conversion -Wno-deprecated-anon-enum-enum-conversion -fdiagnostics-show-option -pthread -Qunused-arguments -ffunction-sections -fdata-sections -fvisibility=hidden -fvisibility-inlines-hidden -g -O0 -DDEBUG -D_DEBUG -- C Compiler: /home/user/opencv/emsdk/upstream/emscripten/emcc -- C flags (Release): -s WASM=1 -s SINGLE_FILE=1 -s USE_PTHREADS=1 -s PTHREAD_POOL_SIZE=8 -msimd128 -s ENVIRONMENT=web,worker -fsigned-char -W -Wall -Wreturn-type -Wnon-virtual-dtor -Waddress -Wsequence-point -Wformat -Wformat-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winconsistent-missing-override -Wno-delete-non-virtual-dtor -Wno-unnamed-type-template-args -Wno-comment -Wno-deprecated-enum-enum-conversion -Wno-deprecated-anon-enum-enum-conversion -fdiagnostics-show-option -pthread -Qunused-arguments -ffunction-sections -fdata-sections -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG -DNDEBUG -- C flags (Debug): -s WASM=1 -s SINGLE_FILE=1 -s USE_PTHREADS=1 -s PTHREAD_POOL_SIZE=8 -msimd128 -s ENVIRONMENT=web,worker -fsigned-char -W -Wall -Wreturn-type -Wnon-virtual-dtor -Waddress -Wsequence-point -Wformat -Wformat-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winconsistent-missing-override -Wno-delete-non-virtual-dtor -Wno-unnamed-type-template-args -Wno-comment -Wno-deprecated-enum-enum-conversion -Wno-deprecated-anon-enum-enum-conversion -fdiagnostics-show-option -pthread -Qunused-arguments -ffunction-sections -fdata-sections -fvisibility=hidden -fvisibility-inlines-hidden -g -O0 -DDEBUG -D_DEBUG -- Linker flags (Release): -Wl,--gc-sections -- Linker flags (Debug): -Wl,--gc-sections -- ccache: NO -- Precompiled headers: NO -- Extra dependencies: -- 3rdparty dependencies: zlib libprotobuf quirc -- -- OpenCV modules: -- To be built: calib3d core dnn features2d flann imgproc js objdetect photo video -- Disabled: highgui imgcodecs ml stitching videoio world -- Disabled by dependency: ts -- Unavailable: gapi java python2 python3 -- Applications: examples -- Documentation: js -- Non-free algorithms: NO -- -- GUI: -- -- Media I/O: -- ZLib: build (ver 1.2.13) -- JPEG 2000: build (ver 2.5.0) -- HDR: YES -- SUNRASTER: YES -- PXM: YES -- PFM: YES -- -- Video I/O: -- -- Parallel framework: pthreads -- -- Other third-party libraries: -- VA: NO -- Custom HAL: NO -- Protobuf: build (3.19.1) -- Flatbuffers: builtin/3rdparty (23.5.9) -- -- Python (for build): /usr/bin/python -- -- Install to: /usr/local -- ----------------------------------------------------------------- -- -- Configuring done

[simonbuehler]

i found out that cv is defined but it is a promise and not the settled object:

console.log(cv) gives [object Promise]

so cv(Module) fails, how should this be handled?

[simonbuehler]

sorry for spamming: even if cv would be resolved - cv is not a function, so whats the idea behind cv(Module), whats that supposed to do ?

[sbc100]

The -sMODULARIZE settings generates a promise which gets resolved when the module is ready. cv(Module) is essentially a constructor fro the module in this case.

[Jove125]

So what's the solution?
How to fix an error in a multi-threaded build? - Adding the -sMODULARIZE setting does not change anything.
Is it correct to comment out this line?

//cv(Module);

[sbc100]

Does it work if you remove the -sMODULARIZE flag from the command line?

[Jove125]

Does it work if you remove the -sMODULARIZE flag from the command line?

No, it does not work.
I didn't have this setting initially (I don't know what it's for). I set --build_wasm --threads only.
But cv is promise in both cases.

I tried to get the result of promise and then call result(Module), but that doesn't work too.
Only works if to comment out this line - cv(Module), but I'm not sure if after this everything works as it should.

[sbc100]

If you are not using -sMODULARIZE (or -sEXPORT_ES6) then I don't see how cv could be a promise and the code in question would never be generated. See how cv(Module) is wrapped in the if MODULARIZE block:

emscripten/src/worker.js

Lines 205 to 211 in 58cf85c

	#if MODULARIZE
	#if MINIMAL_RUNTIME
	{{{ EXPORT_NAME }}}(imports);
	#else
	{{{ EXPORT_NAME }}}(Module);
	#endif
	#endif

Or is the cv(Module) you are seeing coming from somewhere else?

[Jove125]

If you are not using -sMODULARIZE (or -sEXPORT_ES6) then I don't see how cv could be a promise and the code in question would never be generated. See how cv(Module) is wrapped in the if MODULARIZE block:

emscripten/src/worker.js

Lines 205 to 211 in 58cf85c

	#if MODULARIZE
	#if MINIMAL_RUNTIME
	{{{ EXPORT_NAME }}}(imports);
	#else
	{{{ EXPORT_NAME }}}(Module);
	#endif
	#endif

Or is the cv(Module) you are seeing coming from somewhere else?

I looked at the logs. This setting is actually set (implicitly, since I did not specify it):
/home/user/emsdk/upstream/emscripten/em++ -s WASM=1 -s USE_PTHREADS=1 -s PTHREAD_POOL_SIZE=4 -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winconsistent-missing-override -Wno-delete-non-virtual-dtor -Wno-unnamed-type-template-args -Wno-comment -Wno-deprecated-enum-enum-conversion -Wno-deprecated-anon-enum-enum-conversion -fdiagnostics-show-option -pthread -Qunused-arguments -ffunction-sections -fdata-sections -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG -DNDEBUG -Wl,--gc-sections --memory-init-file 0 -s TOTAL_MEMORY=128MB -s WASM_MEM_MAX=1GB -s ALLOW_MEMORY_GROWTH=1 -s MODULARIZE=1 -s SINGLE_FILE=1 -s EXPORT_NAME="'cv'" -s DEMANGLE_SUPPORT=1 -s FORCE_FILESYSTEM=1 --use-preload-plugins --bind --post-js /home/user/opencv/modules/js/src/helpers.js -Wno-missing-prototypes @CMakeFiles/opencv_js.dir/objects1.rsp -o ../../bin/opencv_js.js @CMakeFiles/opencv_js.dir/linklibs.rsp

Should it be disabled for it to work correctly?

[sbc100]

Well, for sure -sMODULARIZE should work in all cases like this, but clearly its causing trouble here, so one way to fix it would be to stop using -sMODULARIZE.

The real fix is to find out why -sMODULARIZE is not working in this case.. but that will require deeper investigation.

BTW, I would also try to remove some of those other settings. For example -sSINGLE_FILE (is the really needed in your case?), -sWASM_MEM_MAX=1GB (that seems like a lot), -s WASM=1 (This is the default so not needed) , -sDEMANGLE_SUPPORT (that setting doesn't really do anything anymore)

[Jove125]

Well, for sure -sMODULARIZE should work in all cases like this, but clearly its causing trouble here, so one way to fix it would be to stop using -sMODULARIZE.

The real fix is to find out why -sMODULARIZE is not working in this case.. but that will require deeper investigation.

BTW, I would also try to remove some of those other settings. For example -sSINGLE_FILE (is the really needed in your case?), -sWASM_MEM_MAX=1GB (that seems like a lot), -s WASM=1 (This is the default so not needed) , -sDEMANGLE_SUPPORT (that setting doesn't really do anything anymore)

Ok, thank you, I'll try to edit default opencv.js settings in CMakeLists.txt