diff options
author | gnzlbg <gonzalobg88@gmail.com> | 2019-02-07 11:37:21 +0100 |
---|---|---|
committer | gnzlbg <gonzalobg88@gmail.com> | 2019-02-07 13:44:32 +0100 |
commit | a17a91cdbf13a43af4e24c0f5498ff6a5e6271c5 (patch) | |
tree | 61e87c1bc93fea6149fa4ac1201059aee3249e09 /build.rs | |
parent | 8f1acf4643293a22c3888423eb9d48d0ee351fa7 (diff) | |
download | rust-libc-a17a91cdbf13a43af4e24c0f5498ff6a5e6271c5.tar.gz |
Fix build on all platforms
This PR fixes the build on all platforms and all Rust version down to the
minimum Rust version supported by libc: Rust 1.13.0.
The `build.rs` is extended with logic to detect the newer Rust features used by
`libc` since Rust 1.13.0:
* Rust 1.19.0: `untagged_unions`. APIs using untagged unions are gated on
`cfg(libc_unions)` and not available on older Rust versions.
* Rust 1.25.0: `repr(align)`. Because `repr(align)` cannot be parsed by older
Rust versions, all uses of `repr(align)` are split into `align.rs` and
`no_align.rs` modules, which are gated on the `cfg(libc_align)` at the top
level. These modules sometimes contain macros that are expanded at the top
level to avoid privacy issues (`pub(crate)` is not available in older Rust
versions). Closes #1242 .
* Rust : `const` `mem::size_of`. These uses are worked around with hardcoded
constants on older Rust versions.
Also, `repr(packed)` structs cannot automatically `derive()` some traits like
`Debug`. These have been moved into `s_no_extra_traits!` and the lint of missing
`Debug` implementations on public items is silenced for these. We can manually
implement the `extra_traits` for these in a follow up PR. This is tracked
in #1243. Also, `extra_traits` does not enable `align` manually anymore.
Since `f64::to_bits` is not available in older Rust versions, its usage
has been replaced with a `transmute` to an `u64` which is what that method
does under the hood.
Closes #1232 .
Diffstat (limited to 'build.rs')
-rw-r--r-- | build.rs | 42 |
1 files changed, 36 insertions, 6 deletions
@@ -3,12 +3,42 @@ use std::process::Command; use std::str; fn main() { - /* - * If `core::ffi::c_void` exists, libc can just re-export it. Otherwise, it - * must define an incompatible type to retain backwards-compatibility. - */ - if rustc_minor_version().expect("Failed to get rustc version") >= 30 { - println!("cargo:rustc-cfg=core_cvoid"); + let rustc_minor_ver = + rustc_minor_version().expect("Failed to get rustc version"); + let rustc_dep_of_std = + std::env::var("CARGO_FEATURE_RUSTC_DEP_OF_STD").is_ok(); + let align_cargo_feature = std::env::var("CARGO_FEATURE_ALIGN").is_ok(); + + // Rust >= 1.15 supports private module use: + if rustc_minor_ver >= 15 || rustc_dep_of_std { + println!("cargo:rustc-cfg=libc_priv_mod_use"); + } + + // Rust >= 1.19 supports unions: + if rustc_minor_ver >= 19 || rustc_dep_of_std { + println!("cargo:rustc-cfg=libc_union"); + } + + // Rust >= 1.24 supports const mem::size_of: + if rustc_minor_ver >= 24 || rustc_dep_of_std { + println!("cargo:rustc-cfg=libc_const_size_of"); + } + + // Rust >= 1.25 supports repr(align): + if rustc_minor_ver >= 25 || rustc_dep_of_std || align_cargo_feature { + println!("cargo:rustc-cfg=libc_align"); + } + + // Rust >= 1.30 supports `core::ffi::c_void`, so libc can just re-export it. + // Otherwise, it defines an incompatible type to retaining + // backwards-compatibility. + if rustc_minor_ver >= 30 || rustc_dep_of_std { + println!("cargo:rustc-cfg=libc_core_cvoid"); + } + + // Rust >= 1.33 supports repr(packed(N)) + if rustc_minor_ver >= 33 || rustc_dep_of_std { + println!("cargo:rustc-cfg=libc_packedN"); } } |