[Build] building for wasm on windows fails due to reference to libiconv #27313
Description
Describe the issue
building for wasm on windows fails due to reference to libiconv
it fails here https://github.com/microsoft/onnxruntime/blob/main/cmake/CMakeLists.txt#L471-L474
Urgency
The issue is urgent, I'm willing to commit a fix, and would appreciate some guidance on how to do so.
Target platform
webassembly
Build script
build --config Release --build_wasm_static_lib --skip_tests --enable_wasm_debug_info --disable_wasm_exception_catching --disable_rtti --enable_wasm_threads --enable_wasm_simd --use_jsep --use_webnn
Error / output
λ build --config Release --build_wasm_static_lib --skip_tests --enable_wasm_debug_info --disable_wasm_exception_catching --disable_rtti --enable_wasm_threads --enable_wasm_simd --use_jsep --use_webnn
2026-02-11 21:50:45,641 tools_python_utils [INFO] - flatbuffers module is not installed. parse_config will not be available
2026-02-11 21:50:45,653 build [DEBUG] - Command line arguments:
--build_dir 'I:\atomica\onnxruntime\build\Windows' --config Release --build_wasm_static_lib --skip_tests --enable_wasm_debug_info --disable_wasm_exception_catching --disable_rtti --enable_wasm_threads --enable_wasm_simd --use_jsep --use_webnn
Namespace(build_dir='I:\atomica\onnxruntime\\build\Windows', config=['Release'], update=True, build=True, clean=False, parallel=1, targets=None, compile_no_warning_as_error=False, build_shared_lib=False, build_apple_framework=False, enable_lto=False, use_cache=False, use_binskim_compliant_compile_flags=False, cmake_extra_defines=[], cmake_path='cmake', cmake_generator='Visual Studio 17 2022', use_vcpkg=False, use_vcpkg_ms_internal_asset_cache=False, skip_submodule_sync=False, skip_pip_install=False, test=False, skip_tests=True, ctest_path='ctest', enable_onnx_tests=False, path_to_protoc_exe=None, cmake_deps_mirror_dir=None, fuzz_testing=False, enable_symbolic_shape_infer_tests=False, skip_onnx_tests=False, skip_winml_tests=False, skip_nodejs_tests=False, ctest_timeout='10800', enable_transformers_tool_test=False, build_micro_benchmarks=False, code_coverage=False, enable_training=False, enable_training_apis=False, enable_training_ops=False, enable_nccl=False, nccl_home=None, enable_memory_profile=False, enable_address_sanitizer=False, gen_doc=None, rv64=False, riscv_toolchain_root='', riscv_qemu_path='', android=False, android_abi='arm64-v8a', android_api=27, android_sdk_path='', android_ndk_path='', android_cpp_shared=False, android_run_emulator=False, build_wasm=False, build_wasm_static_lib=True, emsdk_version='4.0.23', enable_wasm_jspi=False, enable_wasm_simd=True, enable_wasm_relaxed_simd=False, enable_wasm_threads=True, disable_wasm_exception_catching=True, enable_wasm_api_exception_catching=False, enable_wasm_exception_throwing_override=False, wasm_run_tests_in_browser=False, enable_wasm_profiling=False, enable_wasm_debug_info=True, wasm_malloc=None, emscripten_settings=[], use_full_protobuf=False, use_mimalloc=False, external_graph_transformer_path=None, use_extensions=False, extensions_overridden_path=None, minimal_build=None, include_ops_by_config=None, enable_reduced_operator_type_support=False, disable_contrib_ops=False, disable_ml_ops=False, disable_rtti=True, disable_types=[], disable_exceptions=False, client_package_build=False, enable_pybind=False, build_wheel=False, wheel_name_suffix=None, skip_keras_test=False, build_csharp=False, build_nuget=False, msbuild_extra_options=[], build_java=False, build_nodejs=False, build_objc=False, use_cuda=False, cuda_version=None, cuda_home=None, cudnn_home=None, enable_cuda_line_info=False, enable_cuda_nhwc_ops=False, disable_cuda_nhwc_ops=False, enable_cuda_minimal_build=False, nvcc_threads=-1, enable_nvtx_profile=False, enable_cuda_profiling=False, no_sve=False, enable_arm_neon_nchwc=False, use_dnnl=False, dnnl_gpu_runtime='', dnnl_opencl_root='', dnnl_aarch64_runtime='', dnnl_acl_root='', use_openvino=None, use_tensorrt=False, use_tensorrt_builtin_parser=True, use_tensorrt_oss_parser=False, tensorrt_home=None, tensorrt_rtx_home=None, use_nv_tensorrt_rtx=False, use_dml=False, dml_path='', dml_external_project=False, use_nnapi=False, nnapi_min_api=None, use_coreml=False, use_qnn=None, qnn_home=None, use_snpe=False, snpe_root=None, use_vitisai=False, use_armnn=False, armnn_relu=False, armnn_bn=False, armnn_home=None, armnn_libs=None, use_acl=False, acl_home=None, acl_libs=None, no_kleidiai=False, use_qmx=False, use_rknpu=False, use_cann=False, cann_home=None, use_migraphx=False, migraphx_home=None, rocm_version=None, rocm_home=None, use_webnn=True, use_jsep=True, use_webgpu=None, use_external_dawn=False, wgsl_template='static', use_xnnpack=False, use_vsinpu=False, use_azure=False, enable_lazy_tensor=False, ms_experimental=False, enable_msinternal=False, use_lock_free_queue=False, enable_generic_interface=False, msvc_toolset=None, windows_sdk_version=None, enable_msvc_static_runtime=False, use_telemetry=False, caller_framework=None, x86=False, arm=False, arm64=False, arm64ec=False, buildasx=False, disable_memleak_checker=False, enable_pix_capture=False, enable_wcos=False, use_gdk=False, gdk_edition='', gdk_platform='Scarlett', use_winml=False, winml_root_namespace_override=None)
2026-02-11 21:50:45,671 build [INFO] - Build started
2026-02-11 21:50:45,671 build [INFO] - git submodule sync --recursive
Synchronizing submodule url for 'cmake/external/emsdk'
Synchronizing submodule url for 'cmake/external/libprotobuf-mutator'
Synchronizing submodule url for 'cmake/external/onnx'
2026-02-11 21:50:46,523 build [INFO] - git submodule update --init --recursive
2026-02-11 21:50:47,426 build [INFO] - Installing emsdk...
2026-02-11 21:50:47,427 build [INFO] - I:\atomica\onnxruntime\cmake\external\emsdk\emsdk.bat install 4.0.23
Resolving SDK version '4.0.23' to 'sdk-releases-aaa43392544d695232b70eda706d751f18980c2a-64bit'
Installing SDK 'sdk-releases-aaa43392544d695232b70eda706d751f18980c2a-64bit'..
Skipped installing node-22.16.0-64bit, already installed.
Skipped installing python-3.13.3-64bit, already installed.
Skipped installing releases-aaa43392544d695232b70eda706d751f18980c2a-64bit, already installed.
All SDK components already installed: 'sdk-releases-aaa43392544d695232b70eda706d751f18980c2a-64bit'.
2026-02-11 21:50:50,726 build [INFO] - Activating emsdk...
2026-02-11 21:50:50,726 build [INFO] - I:\atomica\onnxruntime\cmake\external\emsdk\emsdk.bat activate 4.0.23
Resolving SDK version '4.0.23' to 'sdk-releases-aaa43392544d695232b70eda706d751f18980c2a-64bit'
Setting the following tools as active:
node-22.16.0-64bit
python-3.13.3-64bit
releases-aaa43392544d695232b70eda706d751f18980c2a-64bit
Next steps:
-
Consider running
emsdk activatewith --permanent or --system
to have emsdk settings available on startup.
The changes made to environment variables only apply to the currently running shell instance. Use the 'emsdk_env.bat' to re-enter this environment later, or if you'd like to register this environment permanently, rerun this command with the option --permanent.
2026-02-11 21:50:51,017 build [INFO] - Generating CMake build tree
2026-02-11 21:50:51,018 build [INFO] - C:\Program Files\CMake\bin\cmake.EXE I:\atomica\onnxruntime\cmake -Donnxruntime_USE_DML=OFF -Donnxruntime_USE_WINML=OFF -Donnxruntime_USE_TELEMETRY=OFF -Donnxruntime_ENABLE_PIX_FOR_WEBGPU_EP=OFF -Donnxruntime_ENABLE_MEMLEAK_CHECKER=ON -Donnxruntime_RUN_ONNX_TESTS=OFF -Donnxruntime_GENERATE_TEST_REPORTS=ON -DPython_EXECUTABLE=C:\Python313\python.exe -Donnxruntime_USE_VCPKG=OFF -Donnxruntime_USE_MIMALLOC=OFF -Donnxruntime_ENABLE_PYTHON=OFF -Donnxruntime_BUILD_CSHARP=OFF -Donnxruntime_BUILD_JAVA=OFF -Donnxruntime_BUILD_NODEJS=OFF -Donnxruntime_BUILD_OBJC=OFF -Donnxruntime_BUILD_SHARED_LIB=OFF -Donnxruntime_BUILD_APPLE_FRAMEWORK=OFF -Donnxruntime_USE_DNNL=OFF -Donnxruntime_USE_NNAPI_BUILTIN=OFF -Donnxruntime_USE_VSINPU=OFF -Donnxruntime_USE_RKNPU=OFF -Donnxruntime_ENABLE_MICROSOFT_INTERNAL=OFF -Donnxruntime_USE_VITISAI=OFF -Donnxruntime_USE_TENSORRT=OFF -Donnxruntime_USE_NV=OFF -Donnxruntime_USE_TENSORRT_BUILTIN_PARSER=ON -Donnxruntime_USE_TENSORRT_INTERFACE=OFF -Donnxruntime_USE_CUDA_INTERFACE=OFF -Donnxruntime_USE_NV_INTERFACE=OFF -Donnxruntime_USE_OPENVINO_INTERFACE=OFF -Donnxruntime_USE_VITISAI_INTERFACE=OFF -Donnxruntime_USE_QNN_INTERFACE=OFF -Donnxruntime_USE_MIGRAPHX_INTERFACE=OFF -Donnxruntime_USE_MIGRAPHX=OFF -Donnxruntime_DISABLE_CONTRIB_OPS=OFF -Donnxruntime_DISABLE_ML_OPS=OFF -Donnxruntime_DISABLE_RTTI=ON -Donnxruntime_DISABLE_EXCEPTIONS=OFF -Donnxruntime_MINIMAL_BUILD=OFF -Donnxruntime_EXTENDED_MINIMAL_BUILD=OFF -Donnxruntime_MINIMAL_BUILD_CUSTOM_OPS=OFF -Donnxruntime_REDUCED_OPS_BUILD=OFF -Donnxruntime_CLIENT_PACKAGE_BUILD=OFF -Donnxruntime_BUILD_MS_EXPERIMENTAL_OPS=OFF -Donnxruntime_ENABLE_LTO=OFF -Donnxruntime_USE_ACL=OFF -Donnxruntime_USE_ARMNN=OFF -Donnxruntime_ARMNN_RELU_USE_CPU=ON -Donnxruntime_ARMNN_BN_USE_CPU=ON -Donnxruntime_USE_JSEP=ON -Donnxruntime_USE_WEBGPU=OFF -Donnxruntime_USE_EXTERNAL_DAWN=OFF -Donnxruntime_WGSL_TEMPLATE=static -Donnxruntime_ENABLE_NVTX_PROFILE=OFF -Donnxruntime_ENABLE_TRAINING=OFF -Donnxruntime_ENABLE_TRAINING_OPS=OFF -Donnxruntime_ENABLE_TRAINING_APIS=OFF -Donnxruntime_ENABLE_CPU_FP16_OPS=OFF -Donnxruntime_USE_NCCL=OFF -Donnxruntime_BUILD_BENCHMARKS=OFF -Donnxruntime_GCOV_COVERAGE=OFF -Donnxruntime_ENABLE_MEMORY_PROFILE=OFF -Donnxruntime_ENABLE_CUDA_LINE_NUMBER_INFO=OFF -Donnxruntime_USE_CUDA_NHWC_OPS=OFF -Donnxruntime_BUILD_WEBASSEMBLY_STATIC_LIB=ON -Donnxruntime_ENABLE_WEBASSEMBLY_EXCEPTION_CATCHING=OFF -Donnxruntime_ENABLE_WEBASSEMBLY_API_EXCEPTION_CATCHING=OFF -Donnxruntime_ENABLE_WEBASSEMBLY_EXCEPTION_THROWING=OFF -Donnxruntime_WEBASSEMBLY_RUN_TESTS_IN_BROWSER=OFF -Donnxruntime_ENABLE_WEBASSEMBLY_JSPI=OFF -Donnxruntime_ENABLE_WEBASSEMBLY_THREADS=ON -Donnxruntime_ENABLE_WEBASSEMBLY_DEBUG_INFO=ON -Donnxruntime_ENABLE_WEBASSEMBLY_PROFILING=OFF -Donnxruntime_ENABLE_LAZY_TENSOR=OFF -Donnxruntime_ENABLE_CUDA_PROFILING=OFF -Donnxruntime_USE_XNNPACK=OFF -Donnxruntime_USE_WEBNN=ON -Donnxruntime_USE_CANN=OFF -Donnxruntime_DISABLE_FLOAT8_TYPES=OFF -Donnxruntime_DISABLE_FLOAT4_TYPES=OFF -Donnxruntime_DISABLE_SPARSE_TENSORS=OFF -Donnxruntime_DISABLE_OPTIONAL_TYPE=OFF -Donnxruntime_CUDA_MINIMAL=OFF -Donnxruntime_ENABLE_WEBASSEMBLY_SIMD=ON -Donnxruntime_USE_WEBNN=ON -Donnxruntime_USE_KLEIDIAI=ON -Donnxruntime_USE_SVE=ON -DCMAKE_TOOLCHAIN_FILE=I:\atomica\onnxruntime\cmake\external\emsdk\upstream\emscripten\cmake\Modules\Platform\Emscripten.cmake -Donnxruntime_BUILD_UNIT_TESTS=OFF -Donnxruntime_EMSCRIPTEN_SETTINGS=MALLOC=dlmalloc;STACK_SIZE=5242880 -DCMAKE_VS_GLOBALS=UseMultiToolTask=true;EnforceProcessCountAcrossBuilds=true -DONNX_USE_MSVC_STATIC_RUNTIME=OFF -Dprotobuf_MSVC_STATIC_RUNTIME=OFF -DABSL_MSVC_STATIC_RUNTIME=OFF -Dgtest_force_shared_crt=ON -G Visual Studio 17 2022 -DCMAKE_BUILD_TYPE=Release
CMake Deprecation Warning at CMakeLists.txt:9 (cmake_policy):
The OLD behavior for policy CMP0104 will be removed from a future version
of CMake.The cmake-policies(7) manual explains that the OLD behaviors of all
policies are deprecated and that a policy should be set to OLD only under
specific short-term circumstances. Projects should be ported to the NEW
behavior and not rely on setting a policy to OLD.
-- The ASM compiler identification is unknown
-- Found assembler: I:/atomica/onnxruntime/cmake/external/emsdk/upstream/emscripten/emcc.bat
-- Warning: Did not find file Compiler/-ASM
-- onnxruntime_target_platform = x86
F16C instruction set is not supported.
FMA instruction set is not supported.
AVX instruction set is not supported.
One or more AVX/F16C instruction flags are not supported.
-- Could NOT find Threads (missing: Threads_FOUND)
CMake Error at C:/Program Files/CMake/share/cmake-4.0/Modules/FindPackageHandleStandardArgs.cmake:227 (message):
Could NOT find Iconv (missing: Iconv_LIBRARY)
Call Stack (most recent call first):
C:/Program Files/CMake/share/cmake-4.0/Modules/FindPackageHandleStandardArgs.cmake:591 (_FPHSA_FAILURE_MESSAGE)
C:/Program Files/CMake/share/cmake-4.0/Modules/FindIconv.cmake:170 (find_package_handle_standard_args)
CMakeLists.txt:470 (find_package)
-- Configuring incomplete, errors occurred!
Traceback (most recent call last):
File "I:\atomica\onnxruntime\tools\ci_build\build.py", line 2684, in
sys.exit(main())
~~~~^^
File "I:\atomica\onnxruntime\tools\ci_build\build.py", line 2552, in main
generate_build_tree(
~~~~~~~~~~~~~~~~~~~^
cmake_path,
^^^^^^^^^^^
...<19 lines>...
cmake_extra_args,
^^^^^^^^^^^^^^^^^
)
^
File "I:\atomica\onnxruntime\tools\ci_build\build.py", line 1326, in generate_build_tree
run_subprocess(
~~~~~~~~~~~~~~^
[*temp_cmake_args, f"-DCMAKE_BUILD_TYPE={config}"],
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...<2 lines>...
env=env,
^^^^^^^^
)
^
File "I:\atomica\onnxruntime\tools\ci_build\build.py", line 148, in run_subprocess
return run(*args, cwd=cwd, capture_stdout=capture_stdout, shell=shell, env=my_env)
File "I:\atomica\onnxruntime\tools\python\util\run.py", line 50, in run
completed_process = subprocess.run(
cmd,
...<6 lines>...
shell=shell,
)
File "C:\Python313\Lib\subprocess.py", line 579, in run
raise CalledProcessError(retcode, process.args,
output=stdout, stderr=stderr)
subprocess.CalledProcessError: Command '['C:\Program Files\CMake\bin\cmake.EXE', 'I:\atomica\onnxruntime\cmake', '-Donnxruntime_USE_DML=OFF', '-Donnxruntime_USE_WINML=OFF', '-Donnxruntime_USE_TELEMETRY=OFF', '-Donnxruntime_ENABLE_PIX_FOR_WEBGPU_EP=OFF', '-Donnxruntime_ENABLE_MEMLEAK_CHECKER=ON', '-Donnxruntime_RUN_ONNX_TESTS=OFF', '-Donnxruntime_GENERATE_TEST_REPORTS=ON', '-DPython_EXECUTABLE=C:\Python313\python.exe', '-Donnxruntime_USE_VCPKG=OFF', '-Donnxruntime_USE_MIMALLOC=OFF', '-Donnxruntime_ENABLE_PYTHON=OFF', '-Donnxruntime_BUILD_CSHARP=OFF', '-Donnxruntime_BUILD_JAVA=OFF', '-Donnxruntime_BUILD_NODEJS=OFF', '-Donnxruntime_BUILD_OBJC=OFF', '-Donnxruntime_BUILD_SHARED_LIB=OFF', '-Donnxruntime_BUILD_APPLE_FRAMEWORK=OFF', '-Donnxruntime_USE_DNNL=OFF', '-Donnxruntime_USE_NNAPI_BUILTIN=OFF', '-Donnxruntime_USE_VSINPU=OFF', '-Donnxruntime_USE_RKNPU=OFF', '-Donnxruntime_ENABLE_MICROSOFT_INTERNAL=OFF', '-Donnxruntime_USE_VITISAI=OFF', '-Donnxruntime_USE_TENSORRT=OFF', '-Donnxruntime_USE_NV=OFF', '-Donnxruntime_USE_TENSORRT_BUILTIN_PARSER=ON', '-Donnxruntime_USE_TENSORRT_INTERFACE=OFF', '-Donnxruntime_USE_CUDA_INTERFACE=OFF', '-Donnxruntime_USE_NV_INTERFACE=OFF', '-Donnxruntime_USE_OPENVINO_INTERFACE=OFF', '-Donnxruntime_USE_VITISAI_INTERFACE=OFF', '-Donnxruntime_USE_QNN_INTERFACE=OFF', '-Donnxruntime_USE_MIGRAPHX_INTERFACE=OFF', '-Donnxruntime_USE_MIGRAPHX=OFF', '-Donnxruntime_DISABLE_CONTRIB_OPS=OFF', '-Donnxruntime_DISABLE_ML_OPS=OFF', '-Donnxruntime_DISABLE_RTTI=ON', '-Donnxruntime_DISABLE_EXCEPTIONS=OFF', '-Donnxruntime_MINIMAL_BUILD=OFF', '-Donnxruntime_EXTENDED_MINIMAL_BUILD=OFF', '-Donnxruntime_MINIMAL_BUILD_CUSTOM_OPS=OFF', '-Donnxruntime_REDUCED_OPS_BUILD=OFF', '-Donnxruntime_CLIENT_PACKAGE_BUILD=OFF', '-Donnxruntime_BUILD_MS_EXPERIMENTAL_OPS=OFF', '-Donnxruntime_ENABLE_LTO=OFF', '-Donnxruntime_USE_ACL=OFF', '-Donnxruntime_USE_ARMNN=OFF', '-Donnxruntime_ARMNN_RELU_USE_CPU=ON', '-Donnxruntime_ARMNN_BN_USE_CPU=ON', '-Donnxruntime_USE_JSEP=ON', '-Donnxruntime_USE_WEBGPU=OFF', '-Donnxruntime_USE_EXTERNAL_DAWN=OFF', '-Donnxruntime_WGSL_TEMPLATE=static', '-Donnxruntime_ENABLE_NVTX_PROFILE=OFF', '-Donnxruntime_ENABLE_TRAINING=OFF', '-Donnxruntime_ENABLE_TRAINING_OPS=OFF', '-Donnxruntime_ENABLE_TRAINING_APIS=OFF', '-Donnxruntime_ENABLE_CPU_FP16_OPS=OFF', '-Donnxruntime_USE_NCCL=OFF', '-Donnxruntime_BUILD_BENCHMARKS=OFF', '-Donnxruntime_GCOV_COVERAGE=OFF', '-Donnxruntime_ENABLE_MEMORY_PROFILE=OFF', '-Donnxruntime_ENABLE_CUDA_LINE_NUMBER_INFO=OFF', '-Donnxruntime_USE_CUDA_NHWC_OPS=OFF', '-Donnxruntime_BUILD_WEBASSEMBLY_STATIC_LIB=ON', '-Donnxruntime_ENABLE_WEBASSEMBLY_EXCEPTION_CATCHING=OFF', '-Donnxruntime_ENABLE_WEBASSEMBLY_API_EXCEPTION_CATCHING=OFF', '-Donnxruntime_ENABLE_WEBASSEMBLY_EXCEPTION_THROWING=OFF', '-Donnxruntime_WEBASSEMBLY_RUN_TESTS_IN_BROWSER=OFF', '-Donnxruntime_ENABLE_WEBASSEMBLY_JSPI=OFF', '-Donnxruntime_ENABLE_WEBASSEMBLY_THREADS=ON', '-Donnxruntime_ENABLE_WEBASSEMBLY_DEBUG_INFO=ON', '-Donnxruntime_ENABLE_WEBASSEMBLY_PROFILING=OFF', '-Donnxruntime_ENABLE_LAZY_TENSOR=OFF', '-Donnxruntime_ENABLE_CUDA_PROFILING=OFF', '-Donnxruntime_USE_XNNPACK=OFF', '-Donnxruntime_USE_WEBNN=ON', '-Donnxruntime_USE_CANN=OFF', '-Donnxruntime_DISABLE_FLOAT8_TYPES=OFF', '-Donnxruntime_DISABLE_FLOAT4_TYPES=OFF', '-Donnxruntime_DISABLE_SPARSE_TENSORS=OFF', '-Donnxruntime_DISABLE_OPTIONAL_TYPE=OFF', '-Donnxruntime_CUDA_MINIMAL=OFF', '-Donnxruntime_ENABLE_WEBASSEMBLY_SIMD=ON', '-Donnxruntime_USE_WEBNN=ON', '-Donnxruntime_USE_KLEIDIAI=ON', '-Donnxruntime_USE_SVE=ON', '-DCMAKE_TOOLCHAIN_FILE=I:\atomica\onnxruntime\cmake\external\emsdk\upstream\emscripten\cmake\Modules\Platform\Emscripten.cmake', '-Donnxruntime_BUILD_UNIT_TESTS=OFF', '-Donnxruntime_EMSCRIPTEN_SETTINGS=MALLOC=dlmalloc;STACK_SIZE=5242880', '-DCMAKE_VS_GLOBALS=UseMultiToolTask=true;EnforceProcessCountAcrossBuilds=true', '-DONNX_USE_MSVC_STATIC_RUNTIME=OFF', '-Dprotobuf_MSVC_STATIC_RUNTIME=OFF', '-DABSL_MSVC_STATIC_RUNTIME=OFF', '-Dgtest_force_shared_crt=ON', '-G', 'Visual Studio 17 2022', '-DCMAKE_BUILD_TYPE=Release']' returned non-zero exit status 1.
Visual Studio Version
No response
GCC / Compiler Version
emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 4.0.23 (7a5d93b50f6a3a35e85a0d2fc9e667b8498e6aed)