prometeu-runtime/files/TODOs.md

PR-3.7 — Integrate GC Cycle at Safepoint (FRAME_SYNC)

Briefing

The GC must only run at safepoints. This PR connects the mark-sweep collector to the VM’s safepoint logic, primarily at FRAME_SYNC.

Target

• Trigger GC cycles only at safepoints.
• Keep execution deterministic.

Work items

• Identify safepoint handling code in the VM.

• Add logic:

  • If allocation threshold exceeded, run GC at FRAME_SYNC.

• Ensure GC does not run in arbitrary instruction contexts.

Acceptance checklist

• GC runs only at safepoints.
• No GC during arbitrary instruction execution.
• VM remains deterministic.
• cargo test passes.

Tests

• Add a test where allocations trigger GC only at FRAME_SYNC.

Junie instructions

You MAY:

• Hook GC invocation into safepoint handling.

You MUST NOT:

• Trigger GC at random points.
• Add background or concurrent GC.

If unclear:

• Ask before modifying safepoint semantics.

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PR-3.8 — GC Smoke and Stress Tests

Briefing

We need confidence that the GC behaves correctly under simple and stressed conditions.

Target

• Add deterministic smoke and stress tests for the GC.

Work items

• Add tests:

  • Simple allocation and collection cycle.
  • Many short-lived objects.
  • Cyclic references.

• Ensure tests are deterministic.

Acceptance checklist

• Smoke tests pass.
• Stress tests pass.
• No nondeterministic failures.
• cargo test passes.

Tests

• New GC-specific tests.

Junie instructions

You MAY:

• Add deterministic tests.

You MUST NOT:

• Introduce random or timing-dependent tests.
• Modify GC semantics to satisfy tests.

If unclear:

• Ask before changing test scenarios.