luaur-code-gen 0.1.0

Native (A64/X64) code generation for Luau (Rust).
Documentation 
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use crate::functions::writeu_64::writeu_64;
use crate::records::unwind_builder_dwarf_2::UnwindBuilderDwarf2;
use crate::records::unwind_function_dwarf_2::UnwindFunctionDwarf2;
use core::ffi::c_char;

impl UnwindBuilderDwarf2 {
    pub fn finalize(
        &self,
        target: *mut c_char,
        offset: usize,
        func_address: *mut core::ffi::c_void,
        block_size: usize,
    ) -> usize {
        unsafe {
            core::ptr::copy_nonoverlapping(
                self.raw_data.as_ptr(),
                target as *mut u8,
                self.get_unwind_info_size(block_size),
            );
        }

        let k_full_block_function: u32 = u32::MAX;
        let target_u8 = target as *mut u8;

        // Constants for DWARF FDE offsets
        const K_FDE_INITIAL_LOCATION_OFFSET: usize = 8;
        const K_FDE_ADDRESS_RANGE_OFFSET: usize = 16;

        for func in &self.unwind_functions {
            unsafe {
                let fde_entry = target_u8.add(func.fde_entry_start_pos as usize);

                writeu_64(
                    fde_entry.add(K_FDE_INITIAL_LOCATION_OFFSET),
                    (func_address as usize as u64) + (offset as u64) + (func.begin_offset as u64),
                );

                let address_range = if func.end_offset == k_full_block_function {
                    (block_size as u64) - (offset as u64)
                } else {
                    (func.end_offset as u64) - (func.begin_offset as u64)
                };

                write_u_64(fde_entry.add(K_FDE_ADDRESS_RANGE_OFFSET), address_range);
            }
        }

        self.unwind_functions.len()
    }
}

#[inline(always)]
unsafe fn write_u_64(target: *mut u8, value: u64) -> *mut u8 {
    writeu_64(target, value)
}