emsdk trying to build eigen using emsdk is throwing assert sys.argv[1][0] == '@', sys.argv in link_wrapper.py

[bakkiraju]

I have the foreign_cc_rules bazel based rule to build eigen like this

maybe(
        http_archive,
        name = "com_gitlab_libeigen_eigen",
        sha256 = "b4c198460eba6f28d34894e3a5710998818515104d6e74e5cc331ce31e46e626",
        strip_prefix = "eigen-3.4.0",
        urls = [
            "https://jfrog.goriv.co/artifactory/gitlab-mirror/libeigen/eigen/-/archive/3.4.0/eigen-3.4.0.tar.bz2",
            "https://gitlab.com/libeigen/eigen/-/archive/3.4.0/eigen-3.4.0.tar.bz2",
        ],
        build_file_content =
            """
load("@rules_foreign_cc//foreign_cc:defs.bzl", "cmake")

filegroup(
    name = "eigen_all",
    srcs = glob(["**"]),
)

cmake(
    name = "eigen",
    lib_source = ":eigen_all",
    out_headers_only = True,
    out_include_dir = "include/eigen3",
    alwayslink = True,
    install = True,
    visibility = ["//visibility:public"],
)
""",
    )

when I try to build it with emsdk, i see link_wrapper.py throwing assertion shown below, is emsdk supposed to work with foreign_rules ?

> _____ BEGIN BUILD LOGS _____
> 
> Bazel external C/C++ Rules. Building library eigen
> 
> Environment:______________
> BUILD_SCRIPT=bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen_foreign_cc/build_script.sh
> EXT_BUILD_ROOT=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware
> BUILD_LOG=bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen_foreign_cc/CMake.log
> PWD=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware
> BUILD_WRAPPER_SCRIPT=bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen_foreign_cc/wrapper_build_script.sh
> TMPDIR=/tmp
> EXT_BUILD_DEPS=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen.ext_build_deps
> NODE_JS_PATH=external/nodejs_linux_amd64/bin/node
> GOPROXY=jfrog.goriv.co/artifactory/rivian-golang-remote
> BUILD_TMPDIR=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen.build_tmpdir
> SHLVL=2
> EM_CONFIG_PATH=external/emscripten_cache/emscripten_config
> EM_BIN_PATH=external/emscripten_bin_linux
> INSTALLDIR=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen
> PATH=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware:/bin:/usr/bin:/usr/local/bin
> EMCC_WASM_BACKEND=1
> _=/bin/env
> __________________________
> + /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/cmake-3.23.2-linux-x86_64/bin/cmake -DCMAKE_TOOLCHAIN_FILE=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen.build_tmpdir/crosstool_bazel.cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen -DCMAKE_PREFIX_PATH=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen.ext_build_deps -DCMAKE_RANLIB= -DCMAKE_MAKE_PROGRAM=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/k8-opt-exec-2B5CBBC6-ST-3d23eae1a3b9/bin/external/rules_foreign_cc/toolchains/make/bin/make -G 'Unix Makefiles' /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/com_gitlab_libeigen_eigen
> -- The C compiler identification is Clang 21.0.0
> -- The CXX compiler identification is Clang 21.0.0
> -- Detecting C compiler ABI info
> -- Detecting C compiler ABI info - done
> -- Check for working C compiler: /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emsdk/emscripten_toolchain/emcc.sh - skipped
> -- Detecting C compile features
> -- Detecting C compile features - done
> -- Detecting CXX compiler ABI info
> -- Detecting CXX compiler ABI info - failed
> -- Check for working CXX compiler: /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emsdk/emscripten_toolchain/emcc.sh
> -- Check for working CXX compiler: /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emsdk/emscripten_toolchain/emcc.sh - broken
> CMake Error at /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/external/cmake-3.23.2-linux-x86_64/share/cmake-3.23/Modules/CMakeTestCXXCompiler.cmake:62 (message):
>   The C++ compiler
> 
>     "/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emsdk/emscripten_toolchain/emcc.sh"
> 
>   is not able to compile a simple test program.
> 
>   It fails with the following output:
> 
>     Change Dir: /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen.build_tmpdir/CMakeFiles/CMakeTmp
>     
>     Run Build Command(s):/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/k8-opt-exec-2B5CBBC6-ST-3d23eae1a3b9/bin/external/rules_foreign_cc/toolchains/make/bin/make -f Makefile cmTC_72731/fast && /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/k8-opt-exec-2B5CBBC6-ST-3d23eae1a3b9/bin/external/rules_foreign_cc/toolchains/make/bin/make  -f CMakeFiles/cmTC_72731.dir/build.make CMakeFiles/cmTC_72731.dir/build
>     make[1]: Entering directory '/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen.build_tmpdir/CMakeFiles/CMakeTmp'
>     Building CXX object CMakeFiles/cmTC_72731.dir/testCXXCompiler.cxx.o
>     /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emsdk/emscripten_toolchain/emcc.sh --sysroot=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emscripten_bin_linux/emscripten/cache/sysroot   --sysroot=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emscripten_bin_linux/emscripten/cache/sysroot -fdiagnostics-color -fno-exceptions -fno-strict-aliasing -funsigned-char -no-canonical-prefixes -std=gnu++17 -nostdinc -nostdinc++ -fomit-frame-pointer -O0 -Wall -iwithsysroot/include/c++/v1 -iwithsysroot/include/compat -iwithsysroot/include -isystem /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emscripten_bin_linux/lib/clang/21/include -Wno-builtin-macro-redefined -D__DATE__=\"redacted\" -D__TIMESTAMP__=\"redacted\" -D__TIME__=\"redacted\"  -MD -MT CMakeFiles/cmTC_72731.dir/testCXXCompiler.cxx.o -MF CMakeFiles/cmTC_72731.dir/testCXXCompiler.cxx.o.d -o CMakeFiles/cmTC_72731.dir/testCXXCompiler.cxx.o -c /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen.build_tmpdir/CMakeFiles/CMakeTmp/testCXXCompiler.cxx
>     Linking CXX executable cmTC_72731
>     /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/external/cmake-3.23.2-linux-x86_64/bin/cmake -E cmake_link_script CMakeFiles/cmTC_72731.dir/link.txt --verbose=1
>     /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emsdk/emscripten_toolchain/emcc_link.sh --sysroot=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emscripten_bin_linux/emscripten/cache/sysroot -fdiagnostics-color -fno-exceptions -fno-strict-aliasing -funsigned-char -no-canonical-prefixes -std=gnu++17 -nostdinc -nostdinc++ -fomit-frame-pointer -O0 -Wall -iwithsysroot/include/c++/v1 -iwithsysroot/include/compat -iwithsysroot/include -isystem /home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emscripten_bin_linux/lib/clang/21/include -Wno-builtin-macro-redefined -D__DATE__=\"redacted\" -D__TIMESTAMP__=\"redacted\" -D__TIME__=\"redacted\"  --sysroot=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emscripten_bin_linux/emscripten/cache/sysroot -fdiagnostics-color -fno-strict-aliasing -funsigned-char -no-canonical-prefixes -s PRINTF_LONG_DOUBLE=1 --oformat=js -O0  CMakeFiles/cmTC_72731.dir/testCXXCompiler.cxx.o -o cmTC_72731 
>     Traceback (most recent call last):
>       File "/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emsdk/emscripten_toolchain/link_wrapper.py", line 25, in <module>
>         assert sys.argv[1][0] == '@', sys.argv
>     AssertionError: ['/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emsdk/emscripten_toolchain/link_wrapper.py', '--sysroot=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emscripten_bin_linux/emscripten/cache/sysroot', '-fdiagnostics-color', '-fno-exceptions', '-fno-strict-aliasing', '-funsigned-char', '-no-canonical-prefixes', '-std=gnu++17', '-nostdinc', '-nostdinc++', '-fomit-frame-pointer', '-O0', '-Wall', '-iwithsysroot/include/c++/v1', '-iwithsysroot/include/compat', '-iwithsysroot/include', '-isystem', '/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emscripten_bin_linux/lib/clang/21/include', '-Wno-builtin-macro-redefined', '-D__DATE__="redacted"', '-D__TIMESTAMP__="redacted"', '-D__TIME__="redacted"', '--sysroot=/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/external/emscripten_bin_linux/emscripten/cache/sysroot', '-fdiagnostics-color', '-fno-strict-aliasing', '-funsigned-char', '-no-canonical-prefixes', '-s', 'PRINTF_LONG_DOUBLE=1', '--oformat=js', '-O0', 'CMakeFiles/cmTC_72731.dir/testCXXCompiler.cxx.o', '-o', 'cmTC_72731']
>     make[1]: *** [CMakeFiles/cmTC_72731.dir/build.make:100: cmTC_72731] Error 1
>     make[1]: Leaving directory '/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen.build_tmpdir/CMakeFiles/CMakeTmp'
>     make: *** [Makefile:127: cmTC_72731/fast] Error 2
>     
>     
> 
>   
> 
>   CMake will not be able to correctly generate this project.
> Call Stack (most recent call first):
>   CMakeLists.txt:4 (project)
> 
> 
> -- Configuring incomplete, errors occurred!
> See also "/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen.build_tmpdir/CMakeFiles/CMakeOutput.log".
> See also "/home/ubuntu/.cache/bazel/_bazel_ubuntu/da60117de278b86dbfdc966eb6b65723/sandbox/linux-sandbox/10/execroot/firmware/bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen.build_tmpdir/CMakeFiles/CMakeError.log".
> _____ END BUILD LOGS _____
> rules_foreign_cc: Build wrapper script location: bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen_foreign_cc/wrapper_build_script.sh
> rules_foreign_cc: Build script location: bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen_foreign_cc/build_script.sh
> rules_foreign_cc: Build log location: bazel-out/wasm-fastbuild-ST-b4dbd4a2bfc4/bin/external/com_gitlab_libeigen_eigen/eigen_foreign_cc/CMake.log
> 

[bakkiraju]

@walkingeyerobot / @kripken Any other existing examples that build a foreign_rules_cc based bazel target using emsdk ?, want to check if I am missing anything or configuring the toolchain incorrectly. Thanks.

[walkingeyerobot]

Unfortunately I don't have any experience with foreign_rules_cc. I think I remember someone else experimenting with it or asking about it, but I'm having trouble digging that up and ultimately I don't think they were able to get it to work.

I suspect the script at bazel/emscripten_toolchain/env.sh isn't going to work for foreign_rules_cc. It's intended only for use with the toolchain and the wasm_cc_binary rule provided in this repo. If you want to use foreign_rules_cc, I would avoid using bazel things in this directory and just try to use emcc directly as your compiler and linker.