Compiler

Layered contracts

Cale does not place every responsibility into one large IR. Each compiler layer has a narrow contract.

• SIR preserves source semantics.
• FIR provides backend-independent SSA-like structure with facts and source anchors.
• BCIR gives backends a stable ABI and object contract.
• Sol is the current backend consumer for assembly, object, and link paths.

This separation makes it easier to locate semantic loss, ABI mismatch, and UB-sensitive lowering bugs.