luaur-analysis 0.1.0

Luau type checker and type inference (Rust).
Documentation 
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use luaur_common::macros::luau_assert::LUAU_ASSERT;
use luaur_common::FFlag;

use crate::functions::paged_allocate::{page_align, page_size};

#[cfg(not(target_os = "windows"))]
use core::ffi::{c_int, c_void};

#[cfg(not(target_os = "windows"))]
extern "C" {
    fn mprotect(addr: *mut c_void, len: usize, prot: c_int) -> c_int;
}

/// Port of `Luau::pagedFreeze`.
///
/// Marks `[ptr, ptr + pageAlign(size))` read-only so that any mutation of a
/// frozen arena traps. Only valid when `DebugLuauFreezeArena` is set and `ptr`
/// is page aligned.
pub fn paged_freeze(ptr: *mut core::ffi::c_void, size: usize) {
    LUAU_ASSERT!(FFlag::DebugLuauFreezeArena.get());
    LUAU_ASSERT!((ptr as usize) % page_size() == 0);

    #[cfg(target_os = "windows")]
    {
        use windows_sys::Win32::System::Memory::{VirtualProtect, PAGE_READONLY};
        let mut old_protect: u32 = 0;
        let rc = unsafe { VirtualProtect(ptr, page_align(size), PAGE_READONLY, &mut old_protect) };
        LUAU_ASSERT!(rc != 0);
    }

    #[cfg(not(target_os = "windows"))]
    {
        const PROT_READ: c_int = 0x1;
        let rc = unsafe { mprotect(ptr as *mut c_void, page_align(size), PROT_READ) };
        LUAU_ASSERT!(rc == 0);
    }
}