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| 1 | +-- SPDX-License-Identifier: MPL-2.0 |
| 2 | +-- Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk> |
| 3 | +-- |
| 4 | +||| Layer 5 — the end-to-end ABI SOUNDNESS CERTIFICATE for Tlaiser. |
| 5 | +||| |
| 6 | +||| Every prior layer proved its own fragment of the contract in isolation: |
| 7 | +||| |
| 8 | +||| * Layer 2 (`Tlaiser.ABI.Semantics`) — the FLAGSHIP safety property: |
| 9 | +||| mutual exclusion holds on every reachable state, witnessed concretely |
| 10 | +||| by `Semantics.positiveControl : Safe (MkSt Critical Idle HeldBy0)` |
| 11 | +||| (the canonical positive-control instance, obtained through the real |
| 12 | +||| INV1 induction over a genuinely reachable state). |
| 13 | +||| |
| 14 | +||| * Layer 3 (`Tlaiser.ABI.Invariants`) — the DEEPER invariant: the |
| 15 | +||| conjunction of two independently-proved inductive invariants |
| 16 | +||| (`Inv` and `HolderCrit`) is itself inductive and therefore holds on |
| 17 | +||| every reachable state, witnessed by |
| 18 | +||| `Invariants.positiveControl : (Inv ..., HolderCrit ...)` on that same |
| 19 | +||| reachable instance. |
| 20 | +||| |
| 21 | +||| * Layer 4 (`Tlaiser.ABI.FfiSeam`) — the FFI SEAM: the wire encoding |
| 22 | +||| `resultToInt` is injective (`FfiSeam.resultToIntInjective`), so distinct |
| 23 | +||| ABI outcomes can never collide on the C boundary. |
| 24 | +||| |
| 25 | +||| This module is the CAPSTONE. It does NOT prove a new domain theorem. It |
| 26 | +||| ASSEMBLES the already-proven, already-exported witnesses of all three |
| 27 | +||| layers into ONE record value, `abiContractDischarged : ABISound`. That |
| 28 | +||| single inhabited value is the certificate: it ties |
| 29 | +||| |
| 30 | +||| manifest -> ABI proofs (flagship safety + deeper invariant) -> FFI seam |
| 31 | +||| |
| 32 | +||| into one end-to-end soundness statement. If ANY prior layer were unsound — |
| 33 | +||| if the flagship safety witness, the conjoined-invariant witness, or the |
| 34 | +||| seam injectivity did not actually typecheck across module boundaries — then |
| 35 | +||| `abiContractDischarged` would fail to elaborate, and this whole capstone |
| 36 | +||| would not build. Genuine composition only: every field is the real exported |
| 37 | +||| fact from the layer that proved it; nothing is fabricated here. |
| 38 | +||| |
| 39 | +||| @see Tlaiser.ABI.Semantics (Layer 2: flagship safety) |
| 40 | +||| @see Tlaiser.ABI.Invariants (Layer 3: conjoined inductive invariant) |
| 41 | +||| @see Tlaiser.ABI.FfiSeam (Layer 4: FFI-seam injectivity) |
| 42 | + |
| 43 | +module Tlaiser.ABI.Capstone |
| 44 | + |
| 45 | +import Tlaiser.ABI.Types |
| 46 | +import Tlaiser.ABI.Semantics |
| 47 | +import Tlaiser.ABI.Invariants |
| 48 | +import Tlaiser.ABI.FfiSeam |
| 49 | + |
| 50 | +%default total |
| 51 | + |
| 52 | +-------------------------------------------------------------------------------- |
| 53 | +-- The end-to-end soundness certificate |
| 54 | +-------------------------------------------------------------------------------- |
| 55 | + |
| 56 | +||| `ABISound` is the conjoined statement that the entire Tlaiser ABI contract |
| 57 | +||| is discharged. Each field is the KEY proven fact of one layer, reusing the |
| 58 | +||| exact exported name from that layer: |
| 59 | +||| |
| 60 | +||| * `flagshipSafety` — Layer 2's headline mutual-exclusion property holds on |
| 61 | +||| the canonical reachable positive-control state `(Critical, Idle, HeldBy0)`. |
| 62 | +||| * `deeperInvariant` — Layer 3's conjoined inductive invariant |
| 63 | +||| (`Inv` ∧ `HolderCrit`) holds on that same reachable state. |
| 64 | +||| * `seamInjective` — Layer 4's FFI wire encoder `resultToInt` is injective, |
| 65 | +||| so the C ABI never confuses two outcomes. |
| 66 | +||| |
| 67 | +||| The record is therefore inhabitable EXACTLY WHEN all three layers are sound. |
| 68 | +public export |
| 69 | +record ABISound where |
| 70 | + constructor MkABISound |
| 71 | + ||| Layer 2 flagship: mutual exclusion on the canonical reachable instance. |
| 72 | + flagshipSafety : Safe (MkSt Critical Idle HeldBy0) |
| 73 | + ||| Layer 3 deeper invariant: the conjoined inductive invariant on that |
| 74 | + ||| same reachable instance. |
| 75 | + deeperInvariant : (Inv (MkSt Critical Idle HeldBy0), HolderCrit (MkSt Critical Idle HeldBy0)) |
| 76 | + ||| Layer 4 FFI seam: the wire encoder is injective. |
| 77 | + seamInjective : (a, b : Result) -> resultToInt a = resultToInt b -> a = b |
| 78 | + |
| 79 | +-------------------------------------------------------------------------------- |
| 80 | +-- The capstone value: the contract, discharged |
| 81 | +-------------------------------------------------------------------------------- |
| 82 | + |
| 83 | +||| THE CAPSTONE. A single inhabited value of `ABISound`, built ONLY from the |
| 84 | +||| real exported witnesses/theorems of the prior layers: |
| 85 | +||| |
| 86 | +||| * `Semantics.positiveControl` (Layer 2 flagship safety positive control), |
| 87 | +||| * `Invariants.positiveControl` (Layer 3 conjoined-invariant positive |
| 88 | +||| control on the same reachable state), |
| 89 | +||| * `FfiSeam.resultToIntInjective` (Layer 4 seam injectivity). |
| 90 | +||| |
| 91 | +||| The two layers each export a `positiveControl`, so they are qualified to the |
| 92 | +||| originating module. This value's mere existence certifies that the manifest |
| 93 | +||| -> ABI proofs -> FFI seam chain is sound end to end. |
| 94 | +public export |
| 95 | +abiContractDischarged : ABISound |
| 96 | +abiContractDischarged = |
| 97 | + MkABISound |
| 98 | + Semantics.positiveControl |
| 99 | + Invariants.positiveControl |
| 100 | + resultToIntInjective |
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