Target-independent layout RTTI (Tier B)

• Type: feature
• Status: done
• Owner: Antigravity
• Blocked-by: feature-cross-bootstrap
• Unblocks: feature-target-arm32, feature-target-i386
• Found / Opened: 2026-06-11

Description

Replace target-specific assembly-code walkers (for managed record retain/release, nested dynamic array release, and copy-on-write dynamic array cloning) with a generic, relative offset-based layout table (RTTI) traversed by target-independent runtime helpers in builtinheap.pas. This allows managed records and dynamic arrays to work across all target architectures (like i386, ARM32, AArch64) without requiring architecture-specific codegen emitters.

Log

• 2026-06-11 — Tier B layout RTTI completed. Added runtime helpers (PXXRecordRetain, PXXRecordRelease, PXXDynArrayRelease, PXXDynArrayUnique) in builtinheap.pas. Added RTTI compiler emission in rtti_emit.inc and resolved references dynamically in ir_codegen.inc to avoid link-time resolution failures for local variables. Fixed System V ABI register-clobbering bug in SetLength loops and fixed dynamic array field RTTI count mapping. All tests compiled, self-bootstrapped, and verified successfully.
• 2026-06-11 — Validation pass: git diff --check, focused dynamic-array/managed-record tests, make test, and make test-nilpy all pass. Follow-up race condition filed as bug-threadsafe-layout-rtti-helper-races. Commit: 58e3803.