SpiderMonkey is Mozilla's JavaScript and WebAssembly Engine, written in C++ and Rust. In BLFS, the source code of SpiderMonkey is taken from Firefox.
![[Note]](../images/note.png) 
          Development versions of BLFS may not build or run some packages properly if LFS or dependencies have been updated since the most recent stable versions of the books.
Download (HTTP): https://archive.mozilla.org/pub/firefox/releases/140.4.0esr/source/firefox-140.4.0esr.source.tar.xz
Download MD5 sum: 2a65419433afc5e1e9876078d857dceb
Download size: 610 MB
Estimated disk space required: 4.7 GB (53 MB installed after removing 42 MB static lib; add 30 MB for the main tests and 30 MB for the jit tests)
Estimated build time: 2.5 SBU (with parallelism=4; add 0.7 SBU for the main tests and 2.5 SBU for the jit tests)
Cbindgen-0.29.2, ICU-77.1, Which-2.23
LLVM-21.1.2 (with Clang, required for 32-bit systems without SSE2 capabilities)
![[Important]](../images/important.png) 
          
            If you are building this package on a 32-bit system, and Clang is
            not installed or you're overriding the default compiler choice
            with the environment variable CXX,
            please read the Command Explanations section first.
          
![[Note]](../images/note.png) 
          
            Unlike most other packages in BLFS, the instructions below
            require you to untar firefox-140.4.0esr.tar.xz and change into the
            firefox-140.4.0 directory.
          
            Extracting the tarball will reset the permissions of the current
            directory to 0755 if you have permission to do that. If you do
            this in a directory where the sticky bit is set, such as
            /tmp it will end with error
            messages:
          
              tar: .: Cannot utime: Operation not permitted
              tar: .: Cannot change mode to rwxr-xr-t: Operation not permitted
              tar: Exiting with failure status due to previous errors
            
            This does finish with non-zero status, but it does NOT mean there is a real problem. Do
            not untar as the root user in a
            directory where the sticky bit is set - that will unset it.
          
Install SpiderMonkey by running the following commands:
![[Note]](../images/note.png) 
          
            If you are compiling this package in chroot you must ensure that
            /dev/shm is mounted. If you do not
            do this, the Python
            configuration will fail with a traceback report referencing
            /usr/lib/pythonN.N/multiprocessing/synchronize.py.
            As the root user, run:
          
mountpoint -q /dev/shm || mount -t tmpfs devshm /dev/shm
Compiling the C++ code respects $MAKEFLAGS and defaults to 'j1', the rust code will use all processors.
mkdir obj &&
cd    obj &&
../js/src/configure --prefix=/usr            \
                    --disable-debug-symbols  \
                    --disable-jemalloc       \
                    --enable-readline        \
                    --enable-rust-simd       \
                    --with-intl-api          \
                    --with-system-icu        \
                    --with-system-zlib       &&
make
        To run the SpiderMonkey test suite, issue:
make -C js/src check-jstests \
     JSTESTS_EXTRA_ARGS="--timeout 300 --wpt=disabled" | tee jstest.log
        
          Because we are building with system ICU, 24 tests (out of a total
          of more than 50,000) are known to fail. The list of failed tests
          can be extracted via grep
          'UNEXPECTED-FAIL' jstest.log. Pass the -c option to grep if you only want the total
          number of failed tests.
        
The test suite is executed with all CPU cores available: even in a cgroup with less cores assigned, it still attempts to spawn as many testing jobs as the number of all cores in the system; fortunately the kernel still won't run these jobs on cores not assigned to the cgroup so the CPU usage is still controlled.
To run the JIT test suite, issue the following command:
make -C js/src check-jit-test
          Like the SpiderMonkey test suite, the number of test jobs is same
          as the number of all CPU cores in the system even if a cgroup is
          used. To make things worse, some test cases can use up to 4 GB of
          system memory, so the peak memory usage may be very large if your
          CPU have multiple cores. Running the JIT test suite without enough
          memory may invoke the kernel OOM killer and cause stability issues.
          If you don't have enough system memory available, append
          JITTEST_EXTRA_ARGS=-j to the command and replace
          NN with the number of test
          jobs your available system memory can hold. For example, if you
          have 15 GB system memory available and 4 CPU cores, append
          JITTEST_EXTRA_ARGS=-j3 to run the test
          suite with 3 parallel jobs so the memory usage won't exceed 12 GB.
        
![[Caution]](../images/caution.png) 
          An issue in the installation process causes any running program which links to SpiderMonkey shared library (for example, GNOME Shell) to crash if SpiderMonkey is reinstalled, or upgraded or downgraded without a change of the major version number (140 in 140.4.0). To work around this issue, remove the old version of the SpiderMonkey shared library before installation:
rm -fv /usr/lib/libmozjs-140.so
          Now, as the root user:
        
make install && rm -v /usr/lib/libjs_static.ajs && sed -i '/@NSPR_CFLAGS@/d' /usr/bin/js140-config
          Still as the root user, fix an
          issue with one of the installed headers:
        
sed '$i#define XP_UNIX' -i /usr/include/mozjs-140/js-config.h
          --disable-debug-symbols:
          Don't generate debug symbols since they are very large and most
          users won't need it. Remove it if you want to debug SpiderMonkey.
        
          --disable-jemalloc: This
          switch disables the internal memory allocator used in SpiderMonkey.
          jemalloc is only intended for the Firefox browser environment. For
          other applications using SpiderMonkey, the application may crash as
          items allocated in the jemalloc allocator are freed on the system
          (glibc) allocator.
        
          --enable-readline: This
          switch enables Readline support in the SpiderMonkey command line
          interface.
        
          --enable-rust-simd: This
          switch enables SIMD optimization in the shipped encoding_rs crate.
        
          --with-intl-api: This
          enables the internationalization functions required by Gjs.
        
          --with-system-*: These
          parameters allow the build system to use system versions of the
          above libraries. These are required for stability.
        
rm -v /usr/lib/libjs_static.ajs: Remove a large static library which is not used by any BLFS package.
sed -i '/@NSPR_CFLAGS@/d' /usr/bin/js140-config: Prevent js140-config from using buggy CFLAGS.
          CC=gcc
          CXX=g++
          CXXFLAGS="-msse2
          -mfpmath=sse"