ABI

[tahadostifam]

• Endianness support for integers.
• Custom alignment feature.
• Bits (Packed Structs)
• Stack Layout
• Target Triple & Data Layout
• Linkage & Visibility
  • Symbol Visibility Attributes: (e.g., default, hidden, protected for ELF). These affect how the linker processes symbols and if they can be overridden.
• C ABI Compatibility
• Exception Handling
  • DWARF unwinding tables, Windows SEH, or other OS-specific mechanisms.
  • Tracing features.

✅ Calling Convention Support (Planned / In Progress)

Support for various calling conventions in the Cyrus Language compiler:

🧩 General Conventions

• "C" — Standard C ABI (platform-specific)
• "system" — Platform-default ABI ("C" on Unix, "stdcall" on Win32)

🪟 Windows-specific Conventions (x86 / x64)

• "stdcall" — Windows API (callee cleans up stack)
• "fastcall" — Pass first args in registers (ECX, EDX)
• "vectorcall" — Optimized for SIMD-heavy code (XMM/AVX regs)
• "thiscall" — Used for instance methods in C++ (ECX holds this)
• "win64" — Official Windows x64 calling convention

🐧 Unix-like (Linux/macOS)

• "sysv64" — System V x86_64 ABI

🧠 Cross-Target ABIs

• "ms_abi" — Microsoft x64 ABI on non-Windows
• "sysv_abi" — SysV ABI on Windows (e.g. mingw interop)

🦾 ARM / Embedded

• "aapcs" — ARM EABI (32-bit)
• "aapcs-vfp" — ARM EABI + floating point registers

⚙️ Special / Platform-specific

• "ccc" — LLVM's internal C calling convention
• "spir_function" — SPIR-V for OpenCL
• "kernel" — GPU kernel launch ABI

---

• Packed structs

If you manually pack a struct, LLVM may lower the alignment to 1 unless you override.
You might want to enforce natural alignment for a field to match a C ABI.

• SIMD types (e.g., v4f32) often need 16-byte alignment.

• Interfacing with external code (*)

If you’re generating globals or structs that will be accessed by C libraries, the alignment must match the ABI expected by the other code.
Example: passing a struct to printf or a library function. Misalignment can cause crashes or undefined behavior on some platforms.