ABI series

Application Binary Interface (ABI) Series

The function call you write is the public API. The ABI call is the private wire format.

A nine-part path through hidden arguments, calling conventions, malformed packets, varargs, ARM64 platform ABIs, unwind metadata, modern FFI, and call-site hardening.

All 9 parts are now live.

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labABI lab: hidden result storage

Part 1The Function Signature Is a LieHidden result storage shows why the source signature is not the whole call.Thesis | Includes hosted trace | May 29, 2026 Lab: Trace hidden result storage

Part 2Same Function, Three RealitiesA side-by-side ABI comparison built around one boring five-integer function.Comparison | Source-backed | Jun 1, 2026

Part 3The Bugs That Make ABI Rules MemorableThe adversarial post in the ABI series: learn ABI rules by watching what breaks when the call packet is malformed.Field guide | Includes hosted trace | Jun 2, 2026 Lab: Trace hidden result storage

Part 4Hidden Arguments Are EverywhereResult storage, receivers, runtime context, and adjusted object pointers are fields the source call may not spell.Hidden fields | Includes hosted trace | Jun 3, 2026 Lab: Trace hidden result storage

Part 5Varargs: The Function Call With Missing Type InformationA focused post on System V AMD64 varargs, Windows x64 floating-point duplication, and the practical advice to avoid variadic FFI.Varargs | Source-backed | Jun 4, 2026

Part 6ARM64 Is Not Just x64 With More RegistersARM64 separates ISA facts from platform ABI rules: link registers, x18, stack policy, and ARM64EC all live at different layers.Platform ABIs | Source-backed | Jun 5, 2026

Part 7It Works Until the Stack Walker ArrivesA post about the failure path: modern ABI contracts must be explainable to unwinders and tooling, not just executable on the sunny path.Unwinding | Source-backed | Jun 8, 2026

Part 8The ABI Is the BoundaryNative boundaries stay hard even when high-level languages make them look ergonomic.Modern boundaries | Source-backed | Jun 9, 2026

Part 9Calls Are Now a Security SurfaceThe finale: calls and returns are no longer just conventions; platforms increasingly enforce parts of the control-flow protocol.Security finale | Source-backed | Jun 10, 2026