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Rollup merge of #82057 - upsuper-forks:cstr, r=davidtwco,wesleywiser

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Replace const_cstr with cstr crate

This PR replaces the `const_cstr` macro inside `rustc_data_structures` with `cstr` macro from [cstr](https://crates.io/crates/cstr) crate.

The two macros basically serve the same purpose, which is to generate `&'static CStr` from a string literal. `cstr` is better because it validates the literal at compile time, while the existing `const_cstr` does it at runtime when `debug_assertions` is enabled. In addition, the value `cstr` generates can be used in constant context (which is seemingly not needed anywhere currently, though).
This commit is contained in:
Dylan DPC 2021-02-27 02:34:21 +01:00 • committed by GitHub
commit cabe97272d
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11 changed files with 42 additions and 60 deletions
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30
compiler/rustc_data_structures/src/const_cstr.rs
View file

@ -1,30 +0,0 @@
/// This macro creates a zero-overhead &CStr by adding a NUL terminator to
/// the string literal passed into it at compile-time. Use it like:
///
/// ```
/// let some_const_cstr = const_cstr!("abc");
/// ```
///
/// The above is roughly equivalent to:
///
/// ```
/// let some_const_cstr = CStr::from_bytes_with_nul(b"abc\0").unwrap()
/// ```
///
/// Note that macro only checks the string literal for internal NULs if
/// debug-assertions are enabled in order to avoid runtime overhead in release
/// builds.
#[macro_export]
macro_rules! const_cstr {
($s:expr) => {{
use std::ffi::CStr;
let str_plus_nul = concat!($s, "\0");
if cfg!(debug_assertions) {
CStr::from_bytes_with_nul(str_plus_nul.as_bytes()).unwrap()
} else {
unsafe { CStr::from_bytes_with_nul_unchecked(str_plus_nul.as_bytes()) }
}
}};
}

1
compiler/rustc_data_structures/src/lib.rs
View file

@ -69,7 +69,6 @@ pub mod base_n;
pub mod binary_search_util;
pub mod box_region;
pub mod captures;
pub mod const_cstr;
pub mod flock;
pub mod functor;
pub mod fx;