Native Backend Options

Required Properties

Consume checked Dever HIR without changing .dever syntax or semantics.
Generate x86_64 and ARM64 ELF, PE/COFF and Mach-O on every supported host.
Run fully offline without Cargo, rustc, a target SDK or a remote build service.
Preserve direct native calls, concrete value layouts and the existing native performance direction.
Keep generated IR, objects and link details private, owned temporary artifacts.
Avoid six target-specific compiler implementations.

Options

Option	Strengths	Blocking weaknesses	Decision
Pinned LLVM code generation plus LLD	Mature optimization; x86_64/ARM64; ELF, PE/COFF and Mach-O; supports in-process use	Large host binaries, native integration boundary, mandatory LLVM notices, target runtimes still required	Recommended
Cranelift plus LLD	Safe Rust-facing library, fast compilation, x86_64/ARM64	Still needs a cross-format linker and target runtimes; optimization quality creates risk against the native performance contract	Keep as fallback only if measured LLVM integration cost is unacceptable
Custom machine-code and executable writers	Full control and small artifacts for the current subset	Reimplements two ISAs, three formats, relocation, unwind and linking; duplicates platform logic and does not scale to the language roadmap	Reject
WebAssembly or a bytecode VM inside native launchers	Simple portable execution model	Changes the AOT/runtime architecture, adds a production VM and jeopardizes native performance requirements	Reject for production build/run
Generated Rust plus bundled or renamed rustc	Reuses current implementation	Exposes the forbidden toolchain, produces Rust temporary source and makes offline target support depend on Rust sysroots/linkers	Replace completely

LLVM's cross-compilation documentation still requires target-specific sysroots/libraries beyond machine-code generation: https://clang.llvm.org/docs/CrossCompilation.html. LLD supports the three required executable formats and can be embedded for compiler-owned trusted objects: https://lld.llvm.org/ and https://lld.llvm.org/NewLLD.html.

Proposed Ownership

dever-core
  checked, target-neutral HIR and source diagnostics

dever-native
  fixed target catalog
  HIR -> LLVM lowering
  object emission
  LLD integration
  target-pack selection
  owned temporary artifacts

dever-runtime
  Dever-owned ABI and runtime behavior
  six release-built target packs

dever-cli
  --target parsing, host/default selection, output and process adaptation

dever-native is one justified private workspace boundary: it isolates the large native dependency and target mechanics from parsing/checking. It is not a public backend plugin API. Target variation uses one explicit catalog and small data/config adapters, not inheritance or a registry.

Build Data Flow

.dever -> check -> typed HIR -> specialize reachable program
       -> shared LLVM lowering -> target object in memory
       -> fixed target specification + versioned Dever runtime pack
       -> embedded LLD driver -> new executable output

LLVM IR and object files are never public output formats.
dever build creates a new output and keeps the current no-overwrite contract.
dever run always builds the host target and runs it; cross-target execution/emulation is not added.
A cross-target build only generates an artifact. Real target runners validate it in release CI.

Target Catalog

The public catalog has exactly six initial targets:

linux-x86_64
linux-arm64
windows-x86_64
windows-arm64
macos-x86_64
macos-arm64

Each target definition owns its LLVM triple, CPU baseline, object format, calling convention, executable suffix, runtime pack and deterministic linker settings. Shared OS and architecture helpers remove repetition; target entries remain explicit and reviewable.

Runtime Packs

Generated code must use a Dever-owned ABI rather than Rust's unstable ABI or Rust String layout. Each target pack contains only Dever-owned startup/runtime objects and permitted platform import metadata. It must not contain Rust standard-library objects, Apple SDK files or target compiler binaries.

The current dever-runtime source is a behavior reference, not a stable native ABI. The first backend milestone defines the minimal Text slice, result/fault and println ABI once, then supplies six compiled implementations or target-specific adapters behind that contract. Future collections, numbers, HTTP, TLS and storage extend this ABI deliberately rather than reaching into host-language layouts.

Determinism And Matrix Verification

Pin one LLVM/LLD source revision and runtime-pack version for all six host builds.
Remove timestamps, absolute build paths, random UUID inputs and host-dependent ordering.
Each of six host compilers builds all six targets, producing 36 artifacts.
Artifacts for the same target and source should be byte-identical across hosts. Hash equality reduces execution validation to one artifact per target; all six target artifacts still run on real matching systems.
Offline checks deny network access and remove Cargo, rustc, Xcode, Visual Studio, GCC and target SDKs from PATH.

Release And License Gates

LLVM permits proprietary distribution but requires its copyright notice in binaries that include it: https://llvm.org/docs/DeveloperPolicy.html#copyright-license-and-patents.
No Apple SDK file may enter a target pack. Apple's agreement prohibits separately using SDKs on non-Apple hardware and redistributing Apple Software in part: https://www.apple.com/legal/sla/docs/xcode.pdf.
Before implementation commits to the macOS target, prove that both Mach-O targets can link the minimal Dever runtime without redistributed Apple SDK material and pass real-machine execution.
The public-compiler Rust attribution decision in distribution-licensing.md remains a product gate.

Rejected Shortcuts

Do not rename or conceal rustc, Cargo, LLD or license files.
Do not special-case the hello example or patch prebuilt executable templates.
Do not implement one backend per OS.
Do not upload source or HIR when local target support is missing.
Do not silently fall back to a VM, host execution or another target.

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