global_asm_wrapper.rs

// Helper macros to deal with platform-specific differences in assembly code
// between ELF, Mach-O and COFF file formats.
cfg_if::cfg_if! {
    if #[cfg(windows)] {
        // COFF
        macro_rules! asm_function_begin {
            ($name:tt) => {
                concat!(
                    ".globl ", $name, "\n",
                    ".def ", $name, "\n",
                    ".scl 2\n",
                    ".type 32\n",
                    ".endef ", $name, "\n",
                    $name, ":\n",
                )
            };
        }
        macro_rules! asm_function_end {
            ($name:tt) => {
                ""
            };
        }
    } else if #[cfg(target_vendor = "apple")] {
        // Mach-O
        macro_rules! asm_function_begin {
            ($name:tt) => {
                concat!(
                    ".globl _", $name, "\n",
                    ".private_extern _", $name, "\n",
                    "_", $name, ":\n",
                )
            };
        }
        macro_rules! asm_function_end {
            ($name:tt) => {
                ""
            };
        }
    } else {
        // Everything else uses ELF
        macro_rules! asm_function_begin {
            ($name:tt) => {
                concat!(
                    ".globl ", $name, "\n",
                    ".hidden ", $name, "\n",
                    ".type ", $name, ", @function\n",
                    $name, ":\n",
                )
            };
        }
        macro_rules! asm_function_end {
            ($name:tt) => {
                concat!(".size ", $name, ", . - ", $name, "\n")
            };
        }
    }
}