Patch #313: Expanding Horizons: Official Windows Cross-Compilation Support

Following our recent expansion into RISC-V and freestanding environments, we are taking another major leap in platform support. We are excited to announce that Wave now officially supports cross-compilation for Windows (x86_64-pc-windows-gnu) from Linux hosts.

By integrating MinGW, Wine, and native Windows LLVM into our build pipeline, we’ve made it possible to develop and package high-performance Windows applications using the Wave toolchain.

1. Seamless Windows Build Pipeline (x.py)

Our universal build script, x.py, has been heavily upgraded to handle the complexities of the Windows ecosystem.

• MinGW Integration: The toolchain now automatically configures itself for x86_64-w64-mingw32-gcc and g++.
• Standalone Binaries: Windows executables often depend on specific runtime libraries. Our new packaging step automatically resolves and bundles essential MinGW DLLs (like libgcc_s_seh-1.dll, libstdc++-6.dll, and libwinpthread-1.dll) alongside your executable. This ensures your Wave programs are truly portable and "just work" on any Windows machine.
• Triple Targeting: You can now build for Windows with a simple command: x.py build x86_64-pc-windows-gnu.

2. Optimized LLVM Backend for Windows

Building a compiler for Windows requires careful handling of backend dependencies and ABI (Application Binary Interface) rules:

• Target Scoping: To speed up compilation and reduce binary bloat, we’ve introduced Cargo feature flags for LLVM. When building for Windows, the compiler now focuses exclusively on llvm-target-x86, avoiding the overhead of irrelevant architectures.
• Custom Windows ABI: We implemented specialized classification rules for the Windows x64 Calling Convention. This ensures that complex structs (SRet/ByVal) and integer extensions are handled exactly as Windows expects, providing 100% compatibility with Windows C libraries.
• Linking Logic: The backend now intelligently skips Linux-specific library injections (like -lc and -lm) when targeting Windows, preventing common linking errors.

3. Native Portability: #[target] Attributes

Our conditional compilation system is now Windows-aware. You can use the #[target(os="windows")] attribute to write code that only runs on Windows systems. This allows you to handle platform-specific tasks—like interacting with the Win32 API—without affecting your Linux or macOS builds.

4. Moving Up the Tiers

As a result of this robust implementation, we have officially promoted Windows (MinGW/GNU) from Tier 4 (Unofficial) to Tier 3 (Experimental) in our platform support policy. While it is still in the experimental stage, it is now a guaranteed part of our build and packaging pipeline.

Conclusion

With Windows support, Wave is becoming a truly universal systems language. Whether you are building high-performance Linux servers, macOS utilities, RISC-V embedded firmware, or now native Windows applications, Wave provides a consistent and powerful experience across all major platforms.

Try building your first .exe with Wave today!

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