Change:
<ins> // Copyright 2012 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. //! Runtime calls emitted by the compiler. use cast::transmute; use libc::{c_char, c_uchar, c_void, size_t, uintptr_t, c_int}; use managed::raw::BoxRepr; use str; use sys; use unstable::exchange_alloc; use cast::transmute; use gc::{cleanup_stack_for_failure, gc, Word}; #[cfg(target_word_size = "32")] pub const FROZEN_BIT: uint = 0x80000000; #[cfg(target_word_size = "64")] pub const FROZEN_BIT: uint = 0x8000000000000000; pub extern mod rustrt { #[rust_stack] unsafe fn rust_upcall_malloc(td: *c_char, size: uintptr_t) -> *c_char; #[rust_stack] unsafe fn rust_upcall_free(ptr: *c_char); } #[lang="fail_"] pub fn fail_(expr: *c_char, file: *c_char, line: size_t) -> ! { sys::begin_unwind_(expr, file, line); } #[lang="fail_bounds_check"] pub unsafe fn fail_bounds_check(file: *c_char, line: size_t, index: size_t, len: size_t) { let msg = fmt!("index out of bounds: the len is %d but the index is %d", len as int, index as int); do str::as_buf(msg) |p, _len| { fail_(p as *c_char, file, line); } } pub unsafe fn fail_borrowed() { let msg = "borrowed"; do str::as_buf(msg) |msg_p, _| { do str::as_buf("???") |file_p, _| { fail_(msg_p as *c_char, file_p as *c_char, 0); } } } // FIXME #4942: Make these signatures agree with exchange_alloc's signatures #[lang="exchange_malloc"] pub unsafe fn exchange_malloc(td: *c_char, size: uintptr_t) -> *c_char { transmute(exchange_alloc::malloc(transmute(td), transmute(size))) } // NB: Calls to free CANNOT be allowed to fail, as throwing an exception from // inside a landing pad may corrupt the state of the exception handler. If a // problem occurs, call exit instead. #[lang="exchange_free"] pub unsafe fn exchange_free(ptr: *c_char) { exchange_alloc::free(transmute(ptr)) } #[lang="malloc"] pub unsafe fn local_malloc(td: *c_char, size: uintptr_t) -> *c_char { return rustrt::rust_upcall_malloc(td, size); } // NB: Calls to free CANNOT be allowed to fail, as throwing an exception from // inside a landing pad may corrupt the state of the exception handler. If a // problem occurs, call exit instead. #[lang="free"] pub unsafe fn local_free(ptr: *c_char) { rustrt::rust_upcall_free(ptr); } #[lang="borrow_as_imm"] #[inline(always)] pub unsafe fn borrow_as_imm(a: *u8) { let a: *mut BoxRepr = transmute(a); (*a).header.ref_count |= FROZEN_BIT; } #[lang="return_to_mut"] #[inline(always)] pub unsafe fn return_to_mut(a: *u8) { let a: *mut BoxRepr = transmute(a); (*a).header.ref_count &= !FROZEN_BIT; } #[lang="check_not_borrowed"] #[inline(always)] pub unsafe fn check_not_borrowed(a: *u8) { let a: *mut BoxRepr = transmute(a); if ((*a).header.ref_count & FROZEN_BIT) != 0 { fail_borrowed(); } } #[lang="strdup_uniq"] pub unsafe fn strdup_uniq(ptr: *c_uchar, len: uint) -> ~str { str::raw::from_buf_len(ptr, len) } #[lang="start"] pub fn start(main: *u8, argc: int, argv: *c_char, crate_map: *u8) -> int { extern { fn rust_start(main: *c_void, argc: c_int, argv: *c_char, crate_map: *c_void) -> c_int; } unsafe { return rust_start(main as *c_void, argc as c_int, argv, crate_map as *c_void) as int; } } // Local Variables: // mode: rust; // fill-column: 78; // indent-tabs-mode: nil // c-basic-offset: 4 // buffer-file-coding-system: utf-8-unix // End: </ins>

Discussion:
This is a public module of things that are exported by core but should not be considered part of the stable library interface. Some don't like the name, and indeed it's name is the opposite of it's form. What should it be renamed to?
Internal, implspecific, dontusethis, unstable, changeable, corehacks?
back?
I like "unstable"; can imagine the future bug report about it changing unexpectedly...
'unstable' sounds good to me to.