XCC

XCC is an alpha C11 compiler written in Python 3.11+ with no runtime dependencies.

Current State

• Frontend: preprocessing, lexing, parsing, semantic analysis, deterministic diagnostics.
• Driver: validates with XCC before backend selection.
• Backends: native macOS arm64 assembly for the implemented subset, strict --backend=xcc, fallback-capable --backend=auto, and explicit --backend=clang.
• Toolchain gap: clang still performs assembly and linking.
• Long-term target: compile CPython without source changes.

Commands

• Install: uv sync --dev
• Test: uv run tox -e py311
• Lint: uv run tox -e lint
• Type check: uv run tox -e type
• Clang fixtures materialize: uv run python scripts/sync_clang_fixtures.py
• Clang fixtures check: uv run python scripts/sync_clang_fixtures.py --check
• Clang fixtures suite: uv run tox -e clang_suite
• Native smoke: uv run tox -e native_smoke
• Linux containers: uv run tox -e docker_glibc or uv run tox -e docker_musl
• Docs: uv run mkdocs build --strict

Rules

• Standard library only at runtime.
• No GPL-derived code or tests.
• 100% line and branch coverage.
• Every behavior change needs a focused test.
• Cached specs and generated upstream fixtures stay uncommitted.