dotnet/runtime · error · RuntimeError

Missing JIT

Error message

Missing JIT

What it means

Thrown by upload_command() when the primary JIT binary (e.g., clrjit.dll, libclrjit.so, libclrjit.dylib) is not found at the expected path in the product (build output) directory. The script computes jit_name via determine_jit_name() based on host_os, then checks os.path.isfile(jit_path); if the file doesn't exist, it logs the path and raises.

Source

Thrown at src/coreclr/scripts/jitrollingbuild.py:388

    #
    # We could also upload debug info, but it's not clear it's needed for most purposes, and it is very big:
    # it increases the upload size from about 190MB to over 900MB for each roll.
    #
    # For reference, the JIT debug info is found:
    #    a. For Windows, in the PDB subdirectory, e.g. PDB\clrjit.pdb
    #    b. For Linux .dbg files, and Mac .dwarf files, in the same directory as the jit, e.g., libcoreclr.so.dbg

    # Target directory: <root>/git-hash/OS/architecture/build-flavor/
    # Note that build-flavor will probably always be Checked.

    files = []

    # First, find the primary JIT that we expect to find.
    jit_name = determine_jit_name(coreclr_args.host_os)
    jit_path = os.path.join(coreclr_args.product_location, jit_name)
    if not os.path.isfile(jit_path):
        logging.error("Error: Couldn't find JIT at {}".format(jit_path))
        raise RuntimeError("Missing JIT")

    files.append(jit_path)

    # Next, look for any and all cross-compilation JITs. These are named, e.g.:
    #   clrjit_unix_x64_x64.dll
    #   clrjit_universal_arm_x64.dll
    #   clrjit_universal_arm64_x64.dll
    # and so on, and live in the same product directory as the primary JIT.
    #
    # Note that the expression below explicitly filters out the primary JIT since we added that above.
    # We handle the primary JIT specially so we can error if it is missing. For the cross-compilation
    # JITs, we don't bother trying to ensure that all the ones we might expect are actually there.
    #
    # We don't do a recursive walk because the JIT is also copied to the "sharedFramework" subdirectory,
    # so we don't want to pick that up.

    if coreclr_args.host_os == "osx":
        allowed_extensions = [ ".dylib" ]

View on GitHub (pinned to 290d5ab72c)

Solutions

1. Verify the build completed successfully: check that os.path.join(product_location, determine_jit_name(host_os)) exists.
2. Ensure -arch and -host_os match the architecture and OS you built for.
3. Check the product_location path — it should typically be the Core_Root or build output directory containing clrjit.dll/libclrjit.so.
4. If only cross-compilation JITs exist, verify whether the primary JIT was built as part of your build configuration.

Example fix

# before: product_location doesn't contain the expected JIT
python jitrollingbuild.py upload -git_hash abc123 -product_location /wrong/path

# after: point to correct build output
python jitrollingbuild.py upload -git_hash abc123 -product_location /artifacts/bin/coreclr/Linux.x64.Checked

# Verify the JIT binary exists before calling upload
import os
from jitutil import determine_jit_name
jit_name = determine_jit_name(coreclr_args.host_os)
jit_path = os.path.join(coreclr_args.product_location, jit_name)
if not os.path.isfile(jit_path):
    print(f'JIT not found at {jit_path}. Build the runtime first.')

def jit_binary_exists(product_location: str, host_os: str) -> bool:
    from jitutil import determine_jit_name
    jit_path = os.path.join(product_location, determine_jit_name(host_os))
    return os.path.isfile(jit_path)

try:
    upload_command(coreclr_args)
except RuntimeError as e:
    if 'Missing JIT' in str(e):
        logging.error('Build the runtime first, then retry upload.')
        sys.exit(1)
    raise

When it happens

Trigger: Called during 'jitrollingbuild.py upload'. Line 384-385: jit_name = determine_jit_name(coreclr_args.host_os); jit_path = os.path.join(coreclr_args.product_location, jit_name). Line 386-388: if not os.path.isfile(jit_path), raise. The product_location must contain the built JIT binary.

Common situations: The .NET runtime hasn't been built yet, or was built for a different OS/architecture than specified. The -product_location or core_root path points to the wrong build output directory. The build completed but the JIT was named differently (e.g., cross-compile JIT with a different naming convention). The build produced only cross-compilation JITs but not the primary clrjit binary.

Related errors

• Error
• Unknown OS.
• Missing azure storage or identity packages.
• Mismatched git hashes between loader and runtime. Loader: ${
• Mismatched git hashes between loader and runtime. Loader: ${

AI-assisted analysis of dotnet/runtime@290d5ab72c (2026-08-06). Data as JSON: /api/errors/b75ee692c19a1dba. Report an issue: GitHub.