oracle/graal · error · IllegalArgumentException

Unexpected architecture name ${archName}

Error message

Unexpected architecture name ${archName}

What it means

createFallbackArchitecture validates the architecture name string (e.g. from a replay header or target spec) against Platform.KNOWN_ARCHITECTURES; an unknown name throws IllegalArgumentException 'Unexpected architecture name <archName>'. The check guards the fallback path that substitutes the host architecture when the replayed target cannot be reconstructed exactly.

Source

Thrown at compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hotspot/replaycomp/BinaryReplayCodec.java:1152

            case AMD64 ignored -> AMD64_ARCHITECTURE;
            case RISCV64 ignored -> RISCV64_ARCHITECTURE;
            case AArch64 ignored -> AARCH64_ARCHITECTURE;
            default -> throw new IllegalArgumentException("Unexpected architecture " + architecture);
        };
    }

    private static void writeArchitectureFeatures(ObjectCopierOutputStream out, Architecture architecture) throws IOException {
        switch (architecture) {
            case AMD64 amd64 -> writeEnumOrdinals(out, amd64.getFeatures());
            case RISCV64 riscv64 -> writeEnumOrdinals(out, riscv64.getFeatures());
            case AArch64 aarch64 -> writeEnumOrdinals(out, aarch64.getFeatures());
            default -> throw new IllegalArgumentException("Unexpected architecture " + architecture);
        }
    }

    private Architecture createFallbackArchitecture(String archName) {
        if (!Platform.KNOWN_ARCHITECTURES.contains(archName)) {
            throw new IllegalArgumentException("Unexpected architecture name " + archName);
        }
        return hostTarget.arch;
    }

    private static Architecture readArchitecture(ObjectCopierInputStream in) throws IOException {
        return switch (in.readPackedUnsignedInt()) {
            case AMD64_ARCHITECTURE -> new AMD64(readEnumOrdinals(in, AMD64.CPUFeature.class));
            case RISCV64_ARCHITECTURE -> new RISCV64(readEnumOrdinals(in, RISCV64.CPUFeature.class));
            case AARCH64_ARCHITECTURE -> new AArch64(readEnumOrdinals(in, AArch64.CPUFeature.class));
            default -> throw new IOException("Unknown replay architecture kind");
        };
    }

    private static void writeEnumOrdinals(ObjectCopierOutputStream out, EnumSet<?> enumSet) throws IOException {
        out.writePackedUnsignedInt(enumSet.size());
        for (Enum<?> constant : enumSet) {
            out.writePackedUnsignedInt(constant.ordinal());
        }

View on GitHub (pinned to a66e9ccd1d)

Solutions

  1. Use a canonical architecture name exactly as listed in Platform.KNOWN_ARCHITECTURES
  2. Re-record the replay file on a build whose Platform knows the architecture
  3. If porting, add the new arch name to Platform.KNOWN_ARCHITECTURES before replaying

Example fix

// before
Architecture a = createFallbackArchitecture("arm64"); // not a known name -> throws

// after
Architecture a = createFallbackArchitecture("aarch64"); // canonical name from Platform.KNOWN_ARCHITECTURES
Defensive patterns

Strategy: validation

Validate before calling

static boolean knownArchitectureName(String name) {
    return Platform.KNOWN_ARCHITECTURES.contains(name);
}

Try / catch

try {
    Architecture a = createFallbackArchitecture(archName);
} catch (IllegalArgumentException e) {
    // unknown arch name: validate against Platform.KNOWN_ARCHITECTURES and correct the config
}

Prevention

When it happens

Trigger: Replaying data whose recorded architecture name is not one of the known architectures (typo, new port name, or corrupted string); invoking the fallback with an arbitrary arch string.

Common situations: Replay files from an in-progress architecture port not yet listed in Platform.KNOWN_ARCHITECTURES; hand-edited configuration specifying an invalid arch name.

Related errors

AI-assisted analysis of oracle/graal@a66e9ccd1d (2026-08-14). Data as JSON: /api/errors/e1ddced89f6a958e. Report an issue: GitHub.