oracle/graal · error · IllegalArgumentException

expected phase_name=filter pair in: {}

Error message

expected phase_name=filter pair in: {}

What it means

PhaseFilterKey.parse (PhaseFilterKey.java:113) splits the filter specification on ':' into phase-name/graph-filter pairs. When a part contains '=' but does not split into exactly two pieces, it throws this IllegalArgumentException. Example bad input: "Phase=a=b".

Source

Thrown at compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/phases/PhaseFilterKey.java:113

        }
    }

    /**
     * Creates a phase filter based on a specification string. The string is a colon-separated list
     * of phase names or {@code phase_name=filter} pairs. Phase names match any phase of which they
     * are a substring. Filters follow {@link MethodFilter} syntax.
     */
    private static BasePhase.PhaseFilter parse(String specification, String phaselessGraphFilterToken) {
        EconomicMap<Pattern, GraphFilter> filters = EconomicMap.create();
        String[] parts = specification.trim().split(":");
        GraphFilter phaselessGraphFilter = null;
        for (String part : parts) {
            String phaseName;
            GraphFilter graphFilter;
            if (part.contains("=")) {
                String[] pair = part.split("=");
                if (pair.length != 2) {
                    throw new IllegalArgumentException("expected phase_name=filter pair in: " + part);
                }
                phaseName = pair[0];
                graphFilter = new GraphFilter(pair[1]);
            } else {
                phaseName = part;
                graphFilter = new GraphFilter(null);
            }
            if (phaseName.equals(phaselessGraphFilterToken)) {
                phaselessGraphFilter = graphFilter;
            } else {
                Pattern phasePattern = Pattern.compile(".*" + MethodFilter.createGlobString(phaseName) + ".*");
                filters.put(phasePattern, graphFilter);
            }
        }
        return new BasePhase.PhaseFilter(filters, phaselessGraphFilter);
    }
}

View on GitHub (pinned to a66e9ccd1d)

Solutions

1. Correct the spec so each part has at most one '=': phaseName=filter pairs separated by ':'
2. Escape or remove '=' characters from the graph filter pattern
3. Re-read the option's javadoc/usage text, which shows the expected 'phase_name=filter' form

Example fix

# before
-Dgraal.PhaseFilter="Escape*=*all=methods"

# after
-Dgraal.PhaseFilter="Escape*=*allmethods"

static void checkPhaseFilter(String spec) {
    for (String part : spec.split(":")) {
        int eq = part.indexOf('=');
        if (eq >= 0 && part.indexOf('=', eq + 1) >= 0) throw new IllegalArgumentException("multiple '=' in: " + part);
    }
}

When it happens

Trigger: A filter spec where one colon-separated part contains more than one '=', e.g., -Dgraal.PhaseFilter="Loop*=foo=bar"; also triggered by a glob pattern that itself contains '='.

Common situations: Typos in the option string; forgetting the MethodFilter glob syntax and using '=' inside the graph filter portion.

Related errors

• Value for {} cannot be empty
• Invalid directed inlining rules file path: {path}
• Could not read directed inlining rules file: {path}
• {file}:{line}: {cause}
• Directed inlining rule must have non-empty caller and callee

AI-assisted analysis of oracle/graal@a66e9ccd1d (2026-08-14). Data as JSON: /api/errors/4e50d0a4f947a727. Report an issue: GitHub.