Export and callbacks — Verification and traceability

Platform spec article

Export and callbacks — Verification and traceability

Back to Export and callbacks ◎ Open feature in platform map

Spec standingStandard

Owner

Piotr Mikstacki pmikstacki@cybernomad.it

Submitter

Piotr Mikstacki pmikstacki@cybernomad.it

Current document

ADRs (4)

1. 0001-hub-authority Feature hub owns normative contract Accepted

   Beskid-to-foreign export authority.

   Context

   Export/callback rules were scattered between runtime and language-meta drafts.

   Decision

   This feature hub must own normative MUST/SHOULD for Beskid export and callback registration (user interop).

   Consequences

   Distinct from runtime builtin exports on Rust ABI profile.

   Verification anchors

   /platform-spec/language-meta/interop/export-and-callbacks/

   Open full ADR page

2. 0002-distinct-from-runtime-builtins User export distinct from runtime builtins Accepted

   Export symbols are generated; builtins stay beskid_abi.

   Context

   Plugin authors confused generated exports with frozen JIT builtin tables.

   Decision

   User export symbols are generated from Beskid compilation units. Frozen runtime builtin exports remain on beskid_abi / Rust ABI profile — export-only work must not change BESKID_RUNTIME_ABI_VERSION.

   Consequences

   Codegen plans export metadata beside ExternImport; trampolines use runtime TLS hooks.

   Verification anchors

   /platform-spec/language-meta/interop/export-and-callbacks/ implementation anchors.

   Open full ADR page

3. 0003-export-pub-functions-v03 Export on pub functions v0.3 Accepted

   Contract vtables as Standard export remain out of scope.

   Context

   Embedding hosts need a minimal stable export surface before full vtable stories.

   Decision

   v0.3 Standard must support [Export] on pub functions with FFI-permitted types. Exporting arbitrary contract vtables as Standard is out of scope for v0.3.

   Consequences

   Callback registration table protocol is Standard; foreign-thread entry without host contract is Proposed v0.3.2+.

   Verification anchors

   export attribute; callback registration.

   Open full ADR page

4. 0004-spec-standard-impl-may-trail Standard spec implementation may trail Accepted

   Normative text can lead reference compiler export support.

   Context

   v0.3 is spec-first for interop; codegen for export is still landing.

   Decision

   This feature is Standard in v0.3 specification. Reference compiler support may trail; verification article records gaps until codegen lands.

   Consequences

   Contributors implement against ADRs without downgrading spec status to Proposed.

   Verification anchors

   verification and traceability.

   Open full ADR page

Articles

• Callback registration Host registration table protocol for Beskid exports invoked from foreign code (v0.3). article Standard Reviewed Sat May 23
• Export attribute Normative Export metadata for pub functions exposed to foreign hosts (v0.3). article Standard Reviewed Wed May 20
• Export and callbacks — Verification and traceability Conformance fixtures for Export and callback registration (v0.3). article Standard Reviewed Sat May 23

History

0 revisions (git unavailable at build; counts may be empty)

Open full history on GitHub

No commits recorded for this path.

Completeness

OKfeature · 3 SpecSection(s) · 1 H2 heading(s)

Full tree: run pnpm verify:platform-spec-layout (writes src/generated/platform-spec-layout-report.json).

Related spec docs

• Feature
  Export and callbacks

  Parent feature hub

Reference compiler status

Surface	Status	Primary verification
[Export(Abi:"C", Symbol:"...")] on pub fn	Implemented (codegen + AOT)	compiler/crates/beskid_engine/tests/ffi_v03_link_time.rs::export_plugin_init_visible_to_linker
Callback registration beskid_register_callbacks + layout band	Implemented (runtime export)	compiler/crates/beskid_engine/tests/ffi_v03_link_time.rs::host_registers_callbacks_with_layout_band
Link-time Extern via project link / external_libraries	Implemented (AOT linker, Linux tier-1)	compiler/crates/beskid_engine/tests/ffi_v03_link_time.rs::link_time_extern_getpid_matches_platform_spec
Export on non-pub function	Codegen diagnostic	compiler/crates/beskid_tests/src/interop/export.rs::export_on_non_pub_function_fails_codegen

Verification anchors

• Engine (Linux tier-1): compiler/crates/beskid_engine/tests/ffi_v03_link_time.rs — link-time getpid, shared-library export visibility, callback layout-band gate.
• Integration: compiler/crates/beskid_tests/src/interop/export.rs, compiler/crates/beskid_tests/src/interop/callback.rs.
• Codegen export metadata: compiler/crates/beskid_codegen/src/lowering/expressions/export.rs, compiler/crates/beskid_codegen/src/lowering/context.rs (CodegenArtifact::exports).
• AOT export table: compiler/crates/beskid_aot/src/export_table.rs.
• Runtime callback registration: compiler/crates/beskid_runtime/src/builtins/callback.rs (beskid_register_callbacks).
• ABI symbols: compiler/crates/beskid_abi/src/symbols.rs (SYM_BESKID_REGISTER_CALLBACKS, BESKID_USER_FFI_LAYOUT_BAND), compiler/crates/beskid_abi/src/builtins.rs (BUILTIN_SPECS).

Runtime ABI

Adding user export symbols must not change RUNTIME_EXPORT_SYMBOLS unless a new runtime-provided registrar is promoted to the Rust ABI profile. beskid_register_callbacks is a runtime export for host registration; user [Export] symbols remain generated from Beskid compilation units.