Cfg: Share more code for switch statements. - #21441
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aschackmull merged 4 commits intoMar 10, 2026
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Pull request overview
This PR centralizes switch-statement control-flow handling in the shared CFG library so that multiple language front-ends (starting with Java and C#) can reuse the same logic.
Changes:
- Extend the shared CFG AST signature for switches to support both “nested case body” and “flat statement list” switch representations.
- Move switch case ordering/body-element handling from the Java CFG implementation into the shared CFG implementation.
- Update Java’s AST signature implementation to conform to the new shared switch/case interface.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| shared/controlflow/codeql/controlflow/ControlFlowGraph.qll | Adds shared switch/case APIs and shared predicates for case ordering and body extraction. |
| java/ql/lib/semmle/code/java/ControlFlowGraph.qll | Removes Java-specific switch CFG helpers now provided by the shared library; implements new shared switch/case APIs. |
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shared/controlflow/codeql/controlflow/ControlFlowGraph.qll
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shared/controlflow/codeql/controlflow/ControlFlowGraph.qll
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hvitved
previously approved these changes
Mar 10, 2026
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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
hvitved
approved these changes
Mar 10, 2026
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Originally I implemented some of the complexity for switch statement control flow on the Java side, but C# needs the exact same thing (and it's plausible other languages will as well), so this PR moves those bits of code into the shared CFG library.
This PR only moves a few predicates and should be completely behaviour preserving.