Performance improvements in libffi

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This article explains a performance optimization approach for libffi, a library that interprets function signatures at runtime. It describes how the existing call path recomputes argument placement on every invocation and why that creates avoidable overhead. The proposed solution builds an immutable call plan once, then reuses it to skip per-call classification work. Benchmarks show the planned path cuts overhead significantly versus ffi_call, especially for common pointer-heavy signatures. The piece also notes that the feature is currently on libffi HEAD and still needs more testing before release.

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