read/cfi: minor CIE/FDE parsing optimisation#866
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philipc merged 1 commit intogimli-rs:masterfrom Jan 20, 2026
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When asked to parse a CIE, we would fully parse any CIE or FDE at the offset, and then discard the result if it was an FDE. Similarly for parsing an FDE. Optimise this by doing the check of the CIE ID immediately. In practice this is unlikely to make any difference, because the entries will always be the expected type if the data is valid. Additionally, we had `Error::NotCieId`, `Error::NotCiePointer`, and `Error::NotFdePointer`, but `Error::NotCiePointer` was not used. However, `Error::NotCiePointer` is the more logical error for the situation where `Error::NotFdePointer` was used, so switch to it and delete `Error::NotFdePointer`. The git history shows that at some point we already did both of the above (which is why `NotCiePointer` existed), but they were lost along the way during refactoring. Also reorder some function parameters for consistency.
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When asked to parse a CIE, we would fully parse any CIE or FDE at the offset, and then discard the result if it was an FDE. Similarly for parsing an FDE. Optimise this by doing the check of the CIE ID immediately. In practice this is unlikely to make any difference, because the entries will always be the expected type if the data is valid.
Additionally, we had
Error::NotCieId,Error::NotCiePointer, andError::NotFdePointer, butError::NotCiePointerwas not used. However,Error::NotCiePointeris the more logical error for the situation whereError::NotFdePointerwas used, so switch to it and deleteError::NotFdePointer.The git history shows that at some point we already did both of the above (which is why
NotCiePointerexisted), but they were lost along the way during refactoring.Also reorder some function parameters for consistency.