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Merged
merged 5 commits into from
Jul 30, 2018
Merged

Add alignment feature and use #[repr(align(x))] #1044

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6abe0b5
Add align feature and use on in6_addr
faern Jul 17, 2018
5f38367
Add testing with align feature
faern Jul 20, 2018
41ca29f
Add align feature to sem_t struct
faern Jul 26, 2018
2819634
Add align feature to pthread structs
faern Jul 20, 2018
e167a73
Describe the align feature in the readme
faern Jul 30, 2018
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1 change: 1 addition & 0 deletions Cargo.toml
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Expand Up @@ -20,6 +20,7 @@ appveyor = { repository = "rust-lang/libc", project_name = "rust-lang-libs/libc"
[features]
default = ["use_std"]
use_std = []
align = []

[workspace]
members = ["libc-test"]
10 changes: 10 additions & 0 deletions README.md
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Expand Up @@ -35,6 +35,16 @@ this via:
libc = { version = "0.2", default-features = false }
```

By default libc uses private fields in structs in order to enforce a certain
memory alignment on them. These structs can be hard to instantiate outside of
libc. To make libc use `#[repr(align(x))]`, instead of the private fields,
activate the *align* feature. This requires Rust 1.25 or newer:

```toml
[dependencies]
libc = { version = "0.2", features = ["align"] }
```

## What is libc?

The primary purpose of this crate is to provide all of the definitions necessary
Expand Down
6 changes: 5 additions & 1 deletion ci/run.sh
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Expand Up @@ -79,7 +79,7 @@ if [ "$QEMU" != "" ]; then
exec grep "^PASSED .* tests" $CARGO_TARGET_DIR/out.log
fi

# FIXME: x86_64-unknown-linux-gnux32 fail to compile wihout --release
# FIXME: x86_64-unknown-linux-gnux32 fail to compile without --release
# See https://github.com/rust-lang/rust/issues/45417
opt=
if [ "$TARGET" = "x86_64-unknown-linux-gnux32" ]; then
Expand All @@ -91,4 +91,8 @@ fi
if [ "$TARGET" != "x86_64-rumprun-netbsd" ]; then
cargo test $opt --no-default-features --manifest-path libc-test/Cargo.toml --target $TARGET
fi
# Test the #[repr(align(x))] feature if this is building on Rust >= 1.25
if [ $(rustc --version | sed -E 's/^rustc 1\.([0-9]*)\..*/\1/') -ge 25 ]; then
cargo test $opt --features align --manifest-path libc-test/Cargo.toml --target $TARGET
fi
exec cargo test $opt --manifest-path libc-test/Cargo.toml --target $TARGET
1 change: 1 addition & 0 deletions libc-test/Cargo.toml
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Expand Up @@ -14,6 +14,7 @@ ctest = { git = "https://github.com/alexcrichton/ctest" }
[features]
default = [ "use_std" ]
use_std = [ "libc/use_std" ]
align = [ "libc/align" ]

[[test]]
name = "main"
Expand Down
148 changes: 110 additions & 38 deletions src/fuchsia/mod.rs
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Expand Up @@ -166,8 +166,10 @@ s! {
pub s_addr: in_addr_t,
}

#[cfg_attr(feature = "align", repr(align(4)))]
pub struct in6_addr {
pub s6_addr: [u8; 16],
#[cfg(not(feature = "align"))]
__align: [u32; 0],
}

Expand Down Expand Up @@ -518,14 +520,30 @@ s! {
pub ifa_data: *mut ::c_void
}

#[cfg_attr(all(feature = "align",
target_pointer_width = "32",
any(target_arch = "mips",
target_arch = "arm",
target_arch = "powerpc",
target_arch = "x86_64")),
repr(align(4)))]
#[cfg_attr(all(feature = "align",
any(target_pointer_width = "64",
not(any(target_arch = "mips",
target_arch = "arm",
target_arch = "powerpc",
target_arch = "x86_64")))),
repr(align(8)))]
pub struct pthread_mutex_t {
#[cfg(any(target_arch = "mips",
target_arch = "arm",
target_arch = "powerpc",
all(target_arch = "x86_64",
target_pointer_width = "32")))]
#[cfg(all(not(feature = "align"),
any(target_arch = "mips",
target_arch = "arm",
target_arch = "powerpc",
all(target_arch = "x86_64",
target_pointer_width = "32"))))]
__align: [::c_long; 0],
#[cfg(not(any(target_arch = "mips",
#[cfg(not(any(feature = "align",
target_arch = "mips",
target_arch = "arm",
target_arch = "powerpc",
all(target_arch = "x86_64",
Expand All @@ -534,14 +552,30 @@ s! {
size: [u8; __SIZEOF_PTHREAD_MUTEX_T],
}

#[cfg_attr(all(feature = "align",
target_pointer_width = "32",
any(target_arch = "mips",
target_arch = "arm",
target_arch = "powerpc",
target_arch = "x86_64")),
repr(align(4)))]
#[cfg_attr(all(feature = "align",
any(target_pointer_width = "64",
not(any(target_arch = "mips",
target_arch = "arm",
target_arch = "powerpc",
target_arch = "x86_64")))),
repr(align(8)))]
pub struct pthread_rwlock_t {
#[cfg(any(target_arch = "mips",
target_arch = "arm",
target_arch = "powerpc",
all(target_arch = "x86_64",
target_pointer_width = "32")))]
#[cfg(all(not(feature = "align"),
any(target_arch = "mips",
target_arch = "arm",
target_arch = "powerpc",
all(target_arch = "x86_64",
target_pointer_width = "32"))))]
__align: [::c_long; 0],
#[cfg(not(any(target_arch = "mips",
#[cfg(not(any(feature = "align",
target_arch = "mips",
target_arch = "arm",
target_arch = "powerpc",
all(target_arch = "x86_64",
Expand All @@ -550,39 +584,78 @@ s! {
size: [u8; __SIZEOF_PTHREAD_RWLOCK_T],
}

#[cfg_attr(all(feature = "align",
any(target_pointer_width = "32",
target_arch = "x86_64", target_arch = "powerpc64",
target_arch = "mips64", target_arch = "s390x",
target_arch = "sparc64",
all(target_arch = "aarch64", target_env = "musl"))),
repr(align(4)))]
#[cfg_attr(all(feature = "align",
not(any(target_pointer_width = "32",
target_arch = "x86_64", target_arch = "powerpc64",
target_arch = "mips64", target_arch = "s390x",
target_arch = "sparc64",
all(target_arch = "aarch64", target_env = "musl")))),
repr(align(8)))]
pub struct pthread_mutexattr_t {
#[cfg(any(target_arch = "x86_64", target_arch = "powerpc64",
target_arch = "mips64", target_arch = "s390x",
target_arch = "sparc64"))]
__align: [::c_int; 0],
#[cfg(not(any(target_arch = "x86_64", target_arch = "powerpc64",
#[cfg(all(not(features = "align"),
any(target_arch = "x86_64", target_arch = "powerpc64",
target_arch = "mips64", target_arch = "s390x",
target_arch = "sparc64", target_arch = "aarch64")))]
__align: [::c_long; 0],
#[cfg(all(target_arch = "aarch64", target_env = "gnu"))]
__align: [::c_long; 0],
#[cfg(all(target_arch = "aarch64", target_env = "musl"))]
target_arch = "sparc64",
all(target_arch = "aarch64", target_env = "musl"))))]
__align: [::c_int; 0],
#[cfg(all(not(features = "align"),
not(any(target_arch = "x86_64", target_arch = "powerpc64",
target_arch = "mips64", target_arch = "s390x",
target_arch = "sparc64",
all(target_arch = "aarch64", target_env = "musl")))))]
__align: [::c_long; 0],
size: [u8; __SIZEOF_PTHREAD_MUTEXATTR_T],
}

#[cfg_attr(all(feature = "align",
any(target_env = "musl", target_pointer_width = "32")),
repr(align(4)))]
#[cfg_attr(all(feature = "align",
not(target_env = "musl"),
target_pointer_width = "64"),
repr(align(8)))]
pub struct pthread_rwlockattr_t {
#[cfg(any(target_env = "musl"))]
#[cfg(all(not(feature = "align"), target_env = "musl"))]
__align: [::c_int; 0],
#[cfg(not(any(target_env = "musl")))]
#[cfg(all(not(feature = "align"), not(target_env = "musl")))]
__align: [::c_long; 0],
size: [u8; __SIZEOF_PTHREAD_RWLOCKATTR_T],
}

#[cfg_attr(all(feature = "align",
target_env = "musl",
target_pointer_width = "32"),
repr(align(4)))]
#[cfg_attr(all(feature = "align",
target_env = "musl",
target_pointer_width = "64"),
repr(align(8)))]
#[cfg_attr(all(feature = "align",
not(target_env = "musl"),
target_arch = "x86"),
repr(align(4)))]
#[cfg_attr(all(feature = "align",
not(target_env = "musl"),
not(target_arch = "x86")),
repr(align(8)))]
pub struct pthread_cond_t {
#[cfg(any(target_env = "musl"))]
#[cfg(all(not(feature = "align"), target_env = "musl"))]
__align: [*const ::c_void; 0],
#[cfg(not(any(target_env = "musl")))]
#[cfg(not(any(feature = "align", target_env = "musl")))]
__align: [::c_longlong; 0],
size: [u8; __SIZEOF_PTHREAD_COND_T],
}

#[cfg_attr(feature = "align", repr(align(4)))]
pub struct pthread_condattr_t {
#[cfg(not(feature = "align"))]
__align: [::c_int; 0],
size: [u8; __SIZEOF_PTHREAD_CONDATTR_T],
}
Expand Down Expand Up @@ -2004,18 +2077,17 @@ pub const RTLD_NOW: ::c_int = 0x2;

pub const TCP_MD5SIG: ::c_int = 14;

pub const PTHREAD_MUTEX_INITIALIZER: pthread_mutex_t = pthread_mutex_t {
__align: [],
size: [0; __SIZEOF_PTHREAD_MUTEX_T],
};
pub const PTHREAD_COND_INITIALIZER: pthread_cond_t = pthread_cond_t {
__align: [],
size: [0; __SIZEOF_PTHREAD_COND_T],
};
pub const PTHREAD_RWLOCK_INITIALIZER: pthread_rwlock_t = pthread_rwlock_t {
__align: [],
size: [0; __SIZEOF_PTHREAD_RWLOCK_T],
};
align_const! {
pub const PTHREAD_MUTEX_INITIALIZER: pthread_mutex_t = pthread_mutex_t {
size: [0; __SIZEOF_PTHREAD_MUTEX_T],
};
pub const PTHREAD_COND_INITIALIZER: pthread_cond_t = pthread_cond_t {
size: [0; __SIZEOF_PTHREAD_COND_T],
};
pub const PTHREAD_RWLOCK_INITIALIZER: pthread_rwlock_t = pthread_rwlock_t {
size: [0; __SIZEOF_PTHREAD_RWLOCK_T],
};
}
pub const PTHREAD_MUTEX_NORMAL: ::c_int = 0;
pub const PTHREAD_MUTEX_RECURSIVE: ::c_int = 1;
pub const PTHREAD_MUTEX_ERRORCHECK: ::c_int = 2;
Expand Down
17 changes: 17 additions & 0 deletions src/macros.rs
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Expand Up @@ -69,3 +69,20 @@ macro_rules! f {
macro_rules! __item {
($i:item) => ($i)
}

#[allow(unused_macros)]
macro_rules! align_const {
($($(#[$attr:meta])* pub const $name:ident : $t1:ty = $t2:ident { $($field:tt)* };)*) => ($(
#[cfg(feature = "align")]
$(#[$attr])*
pub const $name : $t1 = $t2 {
$($field)*
};
#[cfg(not(feature = "align"))]
$(#[$attr])*
pub const $name : $t1 = $t2 {
$($field)*
__align: [],
};
)*)
}
2 changes: 2 additions & 0 deletions src/redox/net.rs
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Expand Up @@ -9,8 +9,10 @@ s! {
pub s_addr: in_addr_t,
}

#[cfg_attr(feature = "align", repr(align(4)))]
pub struct in6_addr {
pub s6_addr: [u8; 16],
#[cfg(not(feature = "align"))]
__align: [u32; 0],
}

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2 changes: 2 additions & 0 deletions src/unix/mod.rs
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Expand Up @@ -104,8 +104,10 @@ s! {
pub s_addr: in_addr_t,
}

#[cfg_attr(feature = "align", repr(align(4)))]
pub struct in6_addr {
pub s6_addr: [u8; 16],
#[cfg(not(feature = "align"))]
__align: [u32; 0],
}

Expand Down
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