Cx Dev Log — 2026-05-01

Source: Dev.to

IR Backend Updates

Memory Operations (Commit 6252994)

• Ptr type added to the IR type system (size = 8 bytes, alignment = 8 bytes).
• Three new IR instructions:
  • Alloca – allocates stack space defined by size and alignment.
  • Load – reads a value from a pointer of a specific type.
  • Store – writes a value through a pointer.

The IR validator now includes 43 new checks, enforcing:

• Alloca must have a size > 0 and a power‑of‑two alignment.
• Load and Store require the pointer operand to be typed explicitly as IrType::Ptr.

These extensions are essential for handling memory structures that exceed single‑register values, mirroring infrastructure found in lowering passes for Cranelift or LLVM.

Struct Registry (Commit c95eea6)

• Introduced build_struct_table() which walks every SemanticStmt::StructDef.
• For each struct, field types are lowered and layout is computed via compute_struct_layout() (originally added in Phase 8).
• StructLayoutInfo now records field offsets, sizes, and alignments, and is threaded through LoweringCtx and the lowering functions.
• lower_type now maps SemanticType::Struct(_) to Ok(IrType::Ptr) instead of returning UnsupportedSemanticType.

This mirrors LLVM’s approach of treating structs as pointers, improving computational efficiency. Layout calculation occurs once per struct and is reused across functions, avoiding redundant work.

Submain vs. Main

• Submain: 22 new commits over 34 days, incorporating updates from Phases 10‑11 (error management, overflow controls, optional semicolons).
• Test coverage: 117 tests on submain vs. 78 on main.
• Risk: Prolonged divergence increases integration difficulty and project risk. Merging is urgent.

Next Steps

1. Lower struct field accesses – implement dot‑access lowering using StructLayoutInfo for pointer arithmetic, followed by Load/Store.
2. Lower struct literals – translate SemanticExprKind::StructLit into an Alloca plus Store operations for each field based on layout offsets.
3. Merge submain into main – top priority; 22 new commits and 39 pending tests need integration.

The groundwork is laid for more sophisticated struct handling in Cx. Immediate implementation work and the pending merge are critical to unify project progress.

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