oracle/graal · error · ValueError

Guest launcher '{guest_launcher}' does not resolve to a file

Error message

Guest launcher '{guest_launcher}' does not resolve to a file!

What it means

Raised by the Emscripten host VM in run_stage_run: the guest VM's launcher path (produced by vm.guest_launcher(self)) must be an existing file, because the host will exec it to run the staged program. A missing file means the guest image/staging stage did not produce the expected launcher, and a ValueError aborts the stage.

Source

Thrown at sdk/mx.sdk/mx_sdk_benchmark.py:2090

            cmd = [self.launcher, str(self.staged_program_file_path)]
            s.execute_command(self, cmd)

    def get_stage_runner(self) -> SimpleStageRunner:
        return SimpleStageRunner(self.stages_info, self.bmSuite, self.stages_context)


class PolyBenchEmscriptenHostVm(PolyBenchStagingVm):
    """Host VM that implements Emscripten used for running staged PolyBench programs through a guest-provided launcher."""
    def run_stage_run(self):
        vm = bm_exec_context().get("vm")
        if not isinstance(vm, PolyBenchEmscriptenGuestVm):
            mx.abort(f"{self.__class__.__name__} expects a PolyBenchEmscriptenGuestVm guest VM in the execution context.")
        if vm.host_vm() != self:
            mx.abort(f"Guest VM '{vm.name()}:{vm.config_name()}' is not hosted by '{self.name()}:{self.config_name()}'.")

        guest_launcher = vm.guest_launcher(self)
        if not Path(guest_launcher).is_file():
            raise ValueError(f"Guest launcher '{guest_launcher}' does not resolve to a file!")
        with self.get_stage_runner() as s:
            cmd = [self.launcher, guest_launcher, str(self.staged_program_file_path)]
            s.execute_command(self, cmd)


class PolyBenchEmscriptenGuestVm(mx_benchmark.GuestVm):
    """Abstract PolyBench Guest VM entry for running on an Emscripten host VM."""
    def __init__(self, host_vm=None):
        super().__init__(host_vm)
        self._guest_run_on_java_home_value = None
        self._guest_run_on_java_home_set = False

    def guest_launcher(self, host_vm: PolyBenchEmscriptenHostVm) -> str:
        """
        Return the launcher executable that the Emscripten host should invoke for this guest.
        The returned path must resolve to a file and is used as the first command element.
        """
        raise NotImplementedError()

View on GitHub (pinned to a66e9ccd1d)

Solutions

Re-run the full staged pipeline (image stage then run stage) so the guest launcher is generated under the image output dir.
Verify the guest/host VM pairing in the benchmark command matches (host must be PolyBenchEmscriptenHostVm and guest PolyBenchEmscriptenGuestVm).
Check that the output directory was not cleaned between stages; inspect vm.guest_launcher(self) return value manually.

Example fix

# before
mx benchmark polybench-js -- --stages=run   # launcher not yet generated

# after
mx benchmark polybench-js -- --stages=image,run

Defensive patterns

Strategy: validation

Validate before calling

launcher_path = Path(guest_vm.guest_launcher(host_vm))
if not launcher_path.is_file():
    sys.exit(f"guest launcher missing at {launcher_path}; run the image stage first")

Try / catch

try/except ValueError around the run stage; if raised, re-run the image stage then retry the run stage once.

Prevention

Always run stages as image,run in one invocation for staged benchmarks.
Do not clean output dirs between stages.
Assert guest/host VM pairing before starting long benchmark jobs.

When it happens

Trigger: Running the 'run' stage of a PolyBench Emscripten benchmark where the guest VM (e.g. a GraalWasm/GraalJS guest) did not generate its launcher file, or the guest_launcher() path points into a clean/rotated output directory.

Common situations: Running the run stage without a prior successful image stage (staged-benchmark output missing), stale output dirs from previous runs, or a mismatch between guest and host VM configs in the mx benchmark invocation.

Related errors

AI-assisted analysis of oracle/graal@a66e9ccd1d (2026-08-14). Data as JSON: /api/errors/cc031363fc615572. Report an issue: GitHub.