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Auto merge of #2845 - joshtriplett:version-handling, r=Amanieu
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Remove most version detection and conditionals for older versions of Rust

Per library team decision, drop most of the conditionals, simplifying the code
substantially. Update the README accordingly.

I left the conditional for 1.62, since that *just* shipped, and the conditional for 1.51 pending ratification of a libc MSRV policy.

- Require rust >= 1.15 and drop libc_priv_mod_use conditional
- Require rust >= 1.19 and drop libc_union conditional
- Require rust >= 1.24 and drop libc_const_size_of conditional
- Require rust >= 1.25 and drop libc_align conditional
- Require rust >= 1.26 and drop libc_int128 conditional
- Require rust >= 1.30 and drop libc_core_cvoid conditional
- Require rust >= 1.33 and drop libc_packedN conditional
- Require rust >= 1.33 and drop libc_cfg_target_vendor conditional
- Require rust >= 1.37 and drop libc_underscore_const_names conditional
- Require rust >= 1.40 and drop libc_non_exhaustive conditional
- Remove array size hacks for Rust < 1.47
- README.md: Update version-dependent features

Deferred while discussing libc MSRV policy:

- Require rust >= 1.51 and drop libc_ptr_addr_of conditional
- Require rust >= 1.62 and drop libc_const_extern_fn conditional
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@bors
bors committed Aug 4, 2022
2 parents 431591a + 71ff679 commit b5e9d00
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Showing 144 changed files with 2,213 additions and 3,878 deletions.
14 changes: 0 additions & 14 deletions .github/workflows/bors.yml
View file
Expand Up @@ -204,11 +204,6 @@ jobs:
stable,
beta,
nightly,
1.13.0,
1.19.0,
1.24.0,
1.25.0,
1.30.0,
]
steps:
- uses: rust-lang/simpleinfra/github-actions/cancel-outdated-builds@master
Expand All @@ -234,11 +229,6 @@ jobs:
stable,
beta,
nightly,
1.13.0,
1.19.0,
1.24.0,
1.25.0,
1.30.0,
]
steps:
- uses: rust-lang/simpleinfra/github-actions/cancel-outdated-builds@master
Expand All @@ -259,10 +249,6 @@ jobs:
fail-fast: true
matrix:
toolchain: [
1.19.0,
1.24.0,
1.25.0,
1.30.0,
stable,
]
steps:
Expand Down
3 changes: 2 additions & 1 deletion Cargo.toml
View file
Expand Up @@ -14,6 +14,7 @@ exclude = ["/ci/*", "/.github/*", "/.cirrus.yml", "/triagebot.toml"]
description = """
Raw FFI bindings to platform libraries like libc.
"""
rust-version = "1.47"

[package.metadata.docs.rs]
features = ["const-extern-fn", "extra_traits"]
Expand All @@ -25,7 +26,7 @@ rustc-std-workspace-core = { version = "1.0.0", optional = true }
default = ["std"]
std = []
align = []
rustc-dep-of-std = ['align', 'rustc-std-workspace-core']
rustc-dep-of-std = ['rustc-std-workspace-core']
extra_traits = []
const-extern-fn = []
# use_std is deprecated, use `std` instead
Expand Down
17 changes: 6 additions & 11 deletions README.md
View file
Expand Up @@ -40,23 +40,18 @@ libc = "0.2"

* **deprecated**: `use_std` is deprecated, and is equivalent to `std`.

* **deprecated**: `align` is deprecated (and always enabled).

## Rust version support

The minimum supported Rust toolchain version is currently **Rust 1.13.0**.
The minimum supported Rust toolchain version is currently **Rust 1.47.0** .
(libc does not currently have any policy regarding changes to the minimum
supported Rust version; such policy is a work in progress.) APIs requiring
newer Rust features are only available on newer Rust toolchains:

| Feature | Version |
|----------------------|---------|
| `union` | 1.19.0 |
| `const mem::size_of` | 1.24.0 |
| `repr(align)` | 1.25.0 |
| `extra_traits` | 1.25.0 |
| `core::ffi::c_void` | 1.30.0 |
| `repr(packed(N))` | 1.33.0 |
| `cfg(target_vendor)` | 1.33.0 |
| `const-extern-fn` | 1.62.0 |
| Feature | Version |
|-----------------------|---------|
| `const-extern-fn` | 1.62.0 |

## Platform support

Expand Down
56 changes: 0 additions & 56 deletions build.rs
View file
Expand Up @@ -8,17 +8,9 @@ fn main() {

let (rustc_minor_ver, is_nightly) = rustc_minor_nightly().expect("Failed to get rustc version");
let rustc_dep_of_std = env::var("CARGO_FEATURE_RUSTC_DEP_OF_STD").is_ok();
let align_cargo_feature = env::var("CARGO_FEATURE_ALIGN").is_ok();
let const_extern_fn_cargo_feature = env::var("CARGO_FEATURE_CONST_EXTERN_FN").is_ok();
let libc_ci = env::var("LIBC_CI").is_ok();

if env::var("CARGO_FEATURE_USE_STD").is_ok() {
println!(
"cargo:warning=\"libc's use_std cargo feature is deprecated since libc 0.2.55; \
please consider using the `std` cargo feature instead\""
);
}

// The ABI of libc used by libstd is backward compatible with FreeBSD 10.
// The ABI of libc from crates.io is backward compatible with FreeBSD 11.
//
Expand All @@ -40,58 +32,10 @@ fn main() {
println!("cargo:rustc-cfg=libc_deny_warnings");
}

// 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 >= 1.26 supports i128 and u128:
if rustc_minor_ver >= 26 || rustc_dep_of_std {
println!("cargo:rustc-cfg=libc_int128");
}

// 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)) and cfg(target_vendor).
if rustc_minor_ver >= 33 || rustc_dep_of_std {
println!("cargo:rustc-cfg=libc_packedN");
println!("cargo:rustc-cfg=libc_cfg_target_vendor");
}

// Rust >= 1.40 supports #[non_exhaustive].
if rustc_minor_ver >= 40 || rustc_dep_of_std {
println!("cargo:rustc-cfg=libc_non_exhaustive");
}

if rustc_minor_ver >= 51 || rustc_dep_of_std {
println!("cargo:rustc-cfg=libc_ptr_addr_of");
}

// Rust >= 1.37.0 allows underscores as anonymous constant names.
if rustc_minor_ver >= 37 || rustc_dep_of_std {
println!("cargo:rustc-cfg=libc_underscore_const_names");
}

// #[thread_local] is currently unstable
if rustc_dep_of_std {
println!("cargo:rustc-cfg=libc_thread_local");
Expand Down
17 changes: 0 additions & 17 deletions ci/build.sh
View file
Expand Up @@ -116,22 +116,15 @@ x86_64-unknown-freebsd \
x86_64-unknown-linux-gnu \
x86_64-unknown-linux-musl \
x86_64-unknown-netbsd \
"

RUST_GT_1_13_LINUX_TARGETS="\
arm-unknown-linux-musleabi \
arm-unknown-linux-musleabihf \
armv7-unknown-linux-musleabihf \
sparc64-unknown-linux-gnu \
wasm32-unknown-emscripten \
x86_64-linux-android \
"
RUST_GT_1_19_LINUX_TARGETS="\
aarch64-unknown-linux-musl \
sparcv9-sun-solaris \
wasm32-unknown-unknown \
"
RUST_GT_1_24_LINUX_TARGETS="\
i586-unknown-linux-musl \
"

Expand Down Expand Up @@ -174,16 +167,6 @@ case "${OS}" in
linux*)
TARGETS="${RUST_LINUX_TARGETS}"

if [ "${RUST}" != "1.13.0" ]; then
TARGETS="${TARGETS} ${RUST_GT_1_13_LINUX_TARGETS}"
if [ "${RUST}" != "1.19.0" ]; then
TARGETS="${TARGETS} ${RUST_GT_1_19_LINUX_TARGETS}"
if [ "${RUST}" != "1.24.0" ]; then
TARGETS="${TARGETS} ${RUST_GT_1_24_LINUX_TARGETS}"
fi
fi
fi

if [ "${RUST}" = "nightly" ]; then
TARGETS="${TARGETS} ${RUST_NIGHTLY_LINUX_TARGETS}"
fi
Expand Down
18 changes: 1 addition & 17 deletions libc-test/build.rs
View file
Expand Up @@ -58,15 +58,7 @@ fn do_ctest() {

fn ctest_cfg() -> ctest::TestGenerator {
let mut cfg = ctest::TestGenerator::new();
let libc_cfgs = [
"libc_priv_mod_use",
"libc_union",
"libc_const_size_of",
"libc_align",
"libc_core_cvoid",
"libc_packedN",
"libc_thread_local",
];
let libc_cfgs = ["libc_thread_local"];
for f in &libc_cfgs {
cfg.cfg(f, None);
}
Expand Down Expand Up @@ -330,8 +322,6 @@ fn test_apple(target: &str) {
// FIXME: the array size has been changed since macOS 10.15 ([8] -> [7]).
("statfs", "f_reserved") => true,
("__darwin_arm_neon_state64", "__v") => true,
// MAXPATHLEN is too big for auto-derive traits on arrays.
("vnode_info_path", "vip_path") => true,
_ => false,
}
});
Expand Down Expand Up @@ -2250,8 +2240,6 @@ fn test_freebsd(target: &str) {
("umutex", "m_owner") => true,
// c_has_waiters field is a volatile int32_t
("ucond", "c_has_waiters") => true,
// is PATH_MAX long but tests can't accept multi array as equivalent.
("kinfo_vmentry", "kve_path") => true,

// a_un field is a union
("Elf32_Auxinfo", "a_un") => true,
Expand Down Expand Up @@ -2280,10 +2268,6 @@ fn test_freebsd(target: &str) {
// Anonymous type.
("filestat", "next") => true,

// We ignore this field because we needed to use a hack in order to make rust 1.19
// happy...
("kinfo_proc", "ki_sparestrings") => true,

// `__sem_base` is a private struct field
("semid_ds", "__sem_base") => true,

Expand Down
60 changes: 28 additions & 32 deletions src/fixed_width_ints.rs
View file
Expand Up @@ -20,7 +20,7 @@ pub type uint32_t = u32;
pub type uint64_t = u64;

cfg_if! {
if #[cfg(all(libc_int128, target_arch = "aarch64", not(target_os = "windows")))] {
if #[cfg(all(target_arch = "aarch64", not(target_os = "windows")))] {
// This introduces partial support for FFI with __int128 and
// equivalent types on platforms where Rust's definition is validated
// to match the standard C ABI of that platform.
Expand Down Expand Up @@ -59,41 +59,37 @@ cfg_if! {
/// C __uint128_t (alternate name for [__uint128][])
pub type __uint128_t = u128;

cfg_if! {
if #[cfg(libc_underscore_const_names)] {
macro_rules! static_assert_eq {
($a:expr, $b:expr) => {
const _: [(); $a] = [(); $b];
};
}
macro_rules! static_assert_eq {
($a:expr, $b:expr) => {
const _: [(); $a] = [(); $b];
};
}

// NOTE: if you add more platforms to here, you may need to cfg
// these consts. They should always match the platform's values
// for `sizeof(__int128)` and `_Alignof(__int128)`.
const _SIZE_128: usize = 16;
const _ALIGN_128: usize = 16;
// NOTE: if you add more platforms to here, you may need to cfg
// these consts. They should always match the platform's values
// for `sizeof(__int128)` and `_Alignof(__int128)`.
const _SIZE_128: usize = 16;
const _ALIGN_128: usize = 16;

// Since Rust doesn't officially guarantee that these types
// have compatible ABIs, we const assert that these values have the
// known size/align of the target platform's libc. If rustc ever
// tries to regress things, it will cause a compilation error.
//
// This isn't a bullet-proof solution because e.g. it doesn't
// catch the fact that llvm and gcc disagree on how x64 __int128
// is actually *passed* on the stack (clang underaligns it for
// the same reason that rustc *never* properly aligns it).
static_assert_eq!(core::mem::size_of::<__int128>(), _SIZE_128);
static_assert_eq!(core::mem::align_of::<__int128>(), _ALIGN_128);
// Since Rust doesn't officially guarantee that these types
// have compatible ABIs, we const assert that these values have the
// known size/align of the target platform's libc. If rustc ever
// tries to regress things, it will cause a compilation error.
//
// This isn't a bullet-proof solution because e.g. it doesn't
// catch the fact that llvm and gcc disagree on how x64 __int128
// is actually *passed* on the stack (clang underaligns it for
// the same reason that rustc *never* properly aligns it).
static_assert_eq!(core::mem::size_of::<__int128>(), _SIZE_128);
static_assert_eq!(core::mem::align_of::<__int128>(), _ALIGN_128);

static_assert_eq!(core::mem::size_of::<__uint128>(), _SIZE_128);
static_assert_eq!(core::mem::align_of::<__uint128>(), _ALIGN_128);
static_assert_eq!(core::mem::size_of::<__uint128>(), _SIZE_128);
static_assert_eq!(core::mem::align_of::<__uint128>(), _ALIGN_128);

static_assert_eq!(core::mem::size_of::<__int128_t>(), _SIZE_128);
static_assert_eq!(core::mem::align_of::<__int128_t>(), _ALIGN_128);
static_assert_eq!(core::mem::size_of::<__int128_t>(), _SIZE_128);
static_assert_eq!(core::mem::align_of::<__int128_t>(), _ALIGN_128);

static_assert_eq!(core::mem::size_of::<__uint128_t>(), _SIZE_128);
static_assert_eq!(core::mem::align_of::<__uint128_t>(), _ALIGN_128);
}
}
static_assert_eq!(core::mem::size_of::<__uint128_t>(), _SIZE_128);
static_assert_eq!(core::mem::align_of::<__uint128_t>(), _ALIGN_128);
}
}

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