From 49be10a8179165d24bbb8eb3490c4ca6f94b42c4 Mon Sep 17 00:00:00 2001 From: Daniel Mueller Date: Fri, 1 Nov 2019 07:42:33 -0700 Subject: Update libc crate to 0.2.66 This change updates the libc crate to version 0.2.66. Import subrepo libc/:libc at 4f11029a68040c90acf771976b019c1ef273a8cd --- libc/src/macros.rs | 98 +++++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 89 insertions(+), 9 deletions(-) (limited to 'libc/src/macros.rs') diff --git a/libc/src/macros.rs b/libc/src/macros.rs index 14a2804..f14bbf5 100644 --- a/libc/src/macros.rs +++ b/libc/src/macros.rs @@ -121,16 +121,96 @@ macro_rules! s_no_extra_traits { ); } -#[allow(unused_macros)] -macro_rules! f { - ($(pub fn $i:ident($($arg:ident: $argty:ty),*) -> $ret:ty { - $($body:stmt);* - })*) => ($( - #[inline] - pub unsafe extern fn $i($($arg: $argty),*) -> $ret { - $($body);* +// This is a pretty horrible hack to allow us to conditionally mark +// some functions as 'const', without requiring users of this macro +// to care about the "const-extern-fn" feature. +// +// When 'const-extern-fn' is enabled, we emit the captured 'const' keyword +// in the expanded function. +// +// When 'const-extern-fn' is disabled, we always emit a plain 'pub unsafe extern fn'. +// Note that the expression matched by the macro is exactly the same - this allows +// users of this macro to work whether or not 'const-extern-fn' is enabled +// +// Unfortunately, we need to duplicate most of this macro between the 'cfg_if' blocks. +// This is because 'const unsafe extern fn' won't even parse on older compilers, +// so we need to avoid emitting it at all of 'const-extern-fn'. +// +// Specifically, moving the 'cfg_if' into the macro body will *not* work. +// Doing so would cause the '#[cfg(feature = "const-extern-fn")]' to be emiited +// into user code. The 'cfg' gate will not stop Rust from trying to parse the +// 'pub const unsafe extern fn', so users would get a compiler error even when +// the 'const-extern-fn' feature is disabled +// +// Note that users of this macro need to place 'const' in a weird position +// (after the closing ')' for the arguments, but before the return type). +// This was the only way I could satisfy the following two requirements: +// 1. Avoid ambuguity errors from 'macro_rules!' (which happen when writing '$foo:ident fn' +// 2. Allow users of this macro to mix 'pub fn foo' and 'pub const fn bar' within the same +// 'f!' block +cfg_if! { + if #[cfg(libc_const_extern_fn)] { + #[allow(unused_macros)] + macro_rules! f { + ($(pub $({$constness:ident})* fn $i:ident( + $($arg:ident: $argty:ty),* + ) -> $ret:ty { + $($body:stmt);* + })*) => ($( + #[inline] + pub $($constness)* unsafe extern fn $i($($arg: $argty),* + ) -> $ret { + $($body);* + } + )*) } - )*) + + #[allow(unused_macros)] + macro_rules! const_fn { + ($($({$constness:ident})* fn $i:ident( + $($arg:ident: $argty:ty),* + ) -> $ret:ty { + $($body:stmt);* + })*) => ($( + #[inline] + $($constness)* fn $i($($arg: $argty),* + ) -> $ret { + $($body);* + } + )*) + } + + } else { + #[allow(unused_macros)] + macro_rules! f { + ($(pub $({$constness:ident})* fn $i:ident( + $($arg:ident: $argty:ty),* + ) -> $ret:ty { + $($body:stmt);* + })*) => ($( + #[inline] + pub unsafe extern fn $i($($arg: $argty),* + ) -> $ret { + $($body);* + } + )*) + } + + #[allow(unused_macros)] + macro_rules! const_fn { + ($($({$constness:ident})* fn $i:ident( + $($arg:ident: $argty:ty),* + ) -> $ret:ty { + $($body:stmt);* + })*) => ($( + #[inline] + fn $i($($arg: $argty),* + ) -> $ret { + $($body);* + } + )*) + } + } } #[allow(unused_macros)] -- cgit v1.2.1